A & E-body mirror heads are the same in 1970 only; the bases are different. Starting in 1971, the B and E-body mirrors are identical... there's the 1971-72 style, the 1973-74 style, and the '75-up style (obviously B-car since there's no post-'74 E, though they were also used on F and M-body coupes through 1981), all of which use identical heads. The bases differ by year; 1971-72 being shorter with the screws closer together, '73-'74 having the screws spaced further apart and taller bases (screwed at the same point on the door, moving the mirror head further into the line of sight), and the '75-up style having the tall base with no exposed fasteners.
Obviously, if you're seeking correct, you need a set of pricey '71-'72 only mirrors. If you're looking for that "look" and want to save a bunch of money, you can get the '75-up set much cheaper. Advantages? A cleaner look since you can't see any fasteners, a RH remote adjuster (rather than drilling your dash you can mount the joystick where the lighter is in the ashtray), and if you get a pair from a '79-up car, you'll actually get a useful convex RH glass ("Objects in mirror...") that increases your field of vision. Prior to 1975, there was no RH remote available.
All versions were available in chrome or painted finish; you're buying so it's your choice. Price-wise, yes: they're expensive. The last set of '75-up B-style sport mirrors I sold on eBay brought $187.50 plus shipping.
If you're interested, I have a pair of painted mirrors from a '77 B-body in nice shape that I'd let go for $100 including shipping. The only difference is that the eBay pair had the convex RH glass, this set doesn't. They're complete with hardware, backing plates, and remotes. Only thing missing is the RH remote mounting nut (same thread as all Mopar adjuster nuts). I bought this pair for my LeBaron but found a perfect set of chrome ones with the convex glass so I don't need these. PM me if you're interested.
