Originally Posted by DJ Niner
Checking a few Glock full-size 9mm handguns/photos that I can access, I see that by the DT* ***-series of serial numbers, there was a faint shadow mold-mark on the frame where the third pin hole would eventually be, like they were already using the 3-pin .40 frame mold, but plugging the hole for the third pin when they used it for 9mm frames. I saw the same thing in a DU* ***-series 9mm, so they still hadn't converted to the three-pin frame for the 9mm guns at the time that Glock was made. Checking the user database for date will give you an idea of when those guns were made, if you want to narrow-down the time window.
You answered my question in advance of me asking.
I spotted a DZU*** G19, on a MI forum that looks like a small mold mark where the 3 rd pin would go.It's hard to tell by the pic, but it doesn't look like the 3rd pin on my GUB *** G19
link to the ad
The question is, is a 3 pin better than a 2 pin model? I know it won't have the BTF issue, but it is pricey.