Correct, I think. E bodies kept the pin style calipers for the whole run, '70-74. I'm not entirely sure when the B bodies changed over to sliders, by the parts catalog it looks like '73 was pin type and '74 was sliders but knowing Mopar there was probably some changeover period.
Nope. E-bodies were pin style calipers for the whole run. The spindles changed in '73 but E's kept the pin type calipers. You can check the cross references, look at the brake hoses which are different for the pin style calipers, etc. Or look at the '73 mopar parts catalog. The "V, L" line was A-bodies.
The '74 parts catalog added sliders for the R, W lines, so, '74 lists sliders for A and B bodies. And it specially calls out pin type and slider calipers.