You've hit the nail on the head The first PST IIs (released in 1996) used the PST handles, so what you've got is an fairly early one. Later, they started stamping the handles PST II.
That's a good question, and I don't really know the answer tbh. I've seen equal numbers of each myself, and have traded quite a few in and out!Right now, I have 3 PST IIs, 1 is marked "PST II", the others are like yours. My daughter has one like yours too, so that's 3 out of 4.My "PST II" marked tool, is dated 0903, which is a late model, as they were phased out in 2004, I don't have enough info to say when they changed to the marked handles.
There are also a few out there that Leatherman decided to make out of spare parts and/or repairs. My fist PST II off of eBay, I bought because I thought it was a PST. It appears that Leatherman used half of a PST (dated 0297) and mated it with half of a PST II marked handle containing the scissors (dated 0802). I didn't know any better and saw the PST side labeled Leatherman Tool Portland Oregon on the eBay photo. When I got it in the mail, I was very confused as the other side was marked Leatherman PST II. Either it was a repair job, or it was made from misc parts. So there are even stranger matches out there to look out for.
I`ve got two PST IIs One of each. Unmarked date codes of 0398 and 0498. PST II marked date codes 1198 and 1198. I`ve got another on the way marked PST II that I bought to give to my brother for his birthday. I`ll check the date codes on it when it arrives in a few days.
Mine is dated 0596,one of the first one's they made,and only has leatherman tool in small print,and Portland OR. on the side,besides being one of my favorite tools,it is the same Month and Year that I quit smoking after 40 yrs. &