Here is another pair I've attempted to plate. You might recognize this pair from an earlier thread. I came up with 46L-47L2L. I'm of course less then certain.
For those keeping score at home, here is the why and how of my conclusion.

First, having inner frame lines, means Type II. Not orange brown Type II, narrows the possible plates. Those being; 1L, 2L, 3 and 5L. L=late.
Secondly, the right hand stamp shows a guide dot. That narrows the possible rows of each plate. Those being; third, fifth, seventh and ninth.
With just those two observations I narrow the search from 2,600 to 320.
Next I look for any re cutting. The left hand stamp shows, 'one line recut upper left triangle'. That's a pretty common recut. The right hand stamp, however, has 'two lines recut upper left triangle'. That narrows it a little more. Having them as a pair, even better.
Now I can go to the U.S.PCS site and check their Plating Guide. I'm only looking at the plates I mentioned. I'm noting stamps, only from rows with guide dots. And, that have 'two lines recut upper left triangle'. Then I look for stamps that would be to the left with, 'one line recut'. That created about a dozen possibilities. An example is, plate 1L has only one position with two line recut, that fits my row criteria, 65R. So, I look to see if 64R is listed with one line recut. It is not. Plate 1L is eliminated that quickly!
I then went to the Steven Ruecker site. Looked at photos of the dozen or so stamps still alive in this search.
This is when I look for more subtle clues. A good one for me was, the right side stamp, left (edited for proper content)inner frame line. You can see it is unusually close at the top. Crooked lines seem to be a useful "tell".

The closest match I found for this pair was, 46-47L2L.