Does this look like a 1970 E-body UCA to you guys? The pen is point towards an tube shaped extension towards the inside of the arm.

I believe that "extension" is a retainer for the bushing. As for what type of arm it is, dunno.

from what i remember, that ring was used for "heavy duty/taxi"
service, and i have seen those on every thing, but not necessarily as intended. there doesn't seem to be any rhyme nor reason as to where these things pop up. i have seen these on all body styles and all engine/trans combos, but they are not on all control arms. in the past, i have fabbed those for a couple thou press fit, and installed them on both bushings. they are not retainers, but are used for extra support. i really don't know if it was worth the effort as i wasn't into any handling improvements at the time. it couldn't hurt. i also don't know if they are available re-popped. any one else with more info on these rings ?

I actually make and sell the reinforcement HD sleeves (reproductions) that you speak of, however, the extension you see in that pic is described as a solid extension of the arm, not a bushing shell or sleeve (someone sent me that pic and asked what I thought about it). I've asked for better pics so we'll soon see.

extension of the arm itself you say ? i wonder if it's stamped as such or a weldment or swedge fit ? i have never seen any thing like that before. better pics will be interesting. please share when you get them.