I think M went to X with Midnight Cowboy, grindhouse & drive-in fare usually was R, and everything else was G. They started building the sub-ratings (PG,XXX) from there.
Original ratingsThe original movie ratings (in use 1968–1970) consisted of: * Rated G: General Audiences. All ages admitted...no matter what * Rated M: Suggested for Mature Audiences. Parental discretion advised. * Rated R: Restricted. Persons under 16 are not admitted unless accompanied by parent or adult guardian. * Rated X: Persons under 17 not admitted.Originally, the rating system was to have three classification levels ending with Restricted (similar to the rating system used in most Canadian Provinces at the time) however, pressure from theatre owners influenced the MPAA to create a film rating (X) exclusively for adults to protect theatre owners from complaints and legal procedures. Initially, the X rating wasn't trademarked: under the plan, anyone not submitting his or her film for rating could self-apply the X (or any other symbol or description, except one trademarked by the rating program).The M rating is replacedMany parents were confused as to whether M-rated films contained more mature content than those rated R. This was especially because during the pre-rating years of 1965 to 1968, an earlier form of crude classification allowed more graphic content to be included so long as the film's advertising bore the notation "Suggested for Mature Audiences" (often abbreviated as "SMA"). Some parents even mistakenly thought that an R rating was less serious than a M rating. This confusion led to its replacement in 1970 by the designation GP, for General Patronage: * Rated GP: All Ages Admitted/Parental Guidance SuggestedThe G in GP was meant to designate that the film had no age restrictions on audience admissions (as in the G rating, "All Ages Admitted"), while the P was to inform audiences that although no ages would be restricted, the discretion of parents was suggested. (The auditory similarity between G and GP soon caused this designation to be further revised into the PG rating, an acronym of Parental Guidance.)
As an aside, I agree with Rubio's comment about Clint in FDM. I thought Manco was his weakest character, completely overshadowed by Mortimer to the point of being a useful accessory. He was much better in GBU where he worked well with Eli, these two complementing each other as "good" and ugly counterpoints to the bad.
For B I think they both figured that the gang would enter the bank from the front door, not blow a hole in the rear wall, that is the reason for the quizzical looks.
so what? the bottom line is that Monco was there when Indio announced the plan: he knew the gang was going to rob the bank; they indeed robbed the bank, and now they are fleeing to Los Palmeros, where Monco is gonna meet them. Seems to me like everything is going perfectly to plan, just like Indio said; I can't possibly understand why Monco should be so angry at Mortimer. The fact that the blew the back wall, how should that affect anything? the only theoretical argument I can hear is that Monco and Mortimer had planned to kill the gang while they were in the bank; but now that the gang uses a different method, of blowing the back wall, they are unable to kill them. So now Monco and Mortimer's plan has failed. I am not sure I'd agree with that argument, but even if I did, that still doesn't explain why Monco would be angry at Mortimer. (Monco is the one on the inside; if anything, Monco should be the one with knowledge of how the bank job would be carried out).
Some things you don't notice till after multiple viewings: in the scene where we cut back and forth between Monco and Mortimer looking at the WANTED poster of Indio, notice that during Monco's montage, his eyes move to the line "$10,000 Reward"; then, when we cut to Mortimer's montage, his eyes move to the line "El Indio... DEAD OR ALIVE." It's a wonderful, subtle point that you can't pick up on until after multiple viewings, but it's a nice little hint there: Monco is focused on the reward money, while Mortimer is focused on killing Indio.
My homage to that scene is about one minute into one of my safety videos. The part preceding that is an overall homage to Leone.See http://www.youtube.com/watch?v=S_QeOvt9qEk