Kevin, funny you should ask this. I picked up an 87 last year, couple pics in this post
https://www.garagejournal.com/forum/showthread.php?p=6474650&highlight=Parker#post6474650 Real nice shape other than missing the handle. A while later I came across another Parker for cheap, think it was a fixed base and not a combo, and figured I'd swap the screw since it had a handle. Well you can imagine my surprise when I saw how short the screw out of the 87 was. I inspected it closely expecting to find evidence of a break, nope. Installed the longer screw from the other vise, pat myself on the back for restoring the capacity of the vise. A few months later stumbled across a catalog page and was surprised to see the small opening. So now I'm in a quandary, swap the screw back to keep it original, or leave the longer screw because it actually makes more sense? I have a few catalog page pics from 1916-1925 showing this vise, most show 3-5/8" jaws that open to 4-3/4", but the 1922 page shows 3-1/2" jaws that open to 3". I didn't actually measure mine before I swapped the screw, but there was quite a bit of slide hanging out the back of the static jaw as the screw ran out.