85 shift fork trans concern

Hello all, My bro's looking to buy a 85 with 100k, has a 4 speed in it. Cars clean, paints nice, interior as well. Test drive went well, at least upshifting, but when downshifting it "pops" out of 2nd unless you hold the shifter back. The seller, semidealer guy,said it was a bent shift fork. I had to check my old Motors manual and notice the
shift rods are adjustable. Not that familiar with GM 4 speeds, but it seems to me if it were a shift fork you'd pop out upshifting as well as downshifting. The seller has offered to repair for 300.00 labor and 30.00 for the part on top of the purchase price. I realize this car has some age on it, and miles but is this pretty common or has someone else had the same concern? I'm wondering if it could be a worn sector shaft bushing or if just an adjustment might correct it. I'm not able to check it out myself due to distance and would hate to see my bro spend a lot more $$$ as he's paying top dollar for this ride. Appreciate any help, thanks