I've had an '86 and 2 '87 60's and all had the skinny pins and neither had the reinforcing crossbar. That's not an argument; just 3 data points. Every USA 62 I've had (6) and the JDM 61 had the beefier plates and the matching dog-legged shock mount crossmember.
It would be interesting to find...
4+ plates use the smaller diameter pins. They match the 60's but not the 62's. Easy fix to swap shock mount bushing for 62 owners.
As previously stated, OEM RH extended plate is to accommodate factory cable locker.