There is now a specialty catalog for Poland orts called Shatalin (or Szatalin) and nobody is using Kopicki any more, unfortunately.
I think the key features of your coin are the Obverse legend ending in PRVS MAS (not PRV MAS, PRVS M, or any other permutation), and beginning with SIGIS III (not SIGI). And then, as you point out the single dot after GOT, rather than a colon (:). I don;t have Kopicki (though I probably should) to see which type fits.
But as pointed out by Marc16, there are MANY die varieties for the Sigismund orts. For 1621 with SIGIS … PRVS MAS obverse , and GOT . reverse here are a few:
https://www.acsearch.info/search.html?id=12353503 Shatalin 21-II- 18, but the band on the crown reverse does not match
https://www.acsearch.info/search.html?id=7365705 Shatalin BD21-55. Possibly an exact obverse die match, with the tilted S in MAS and I think all same punctuation. The reverse is also very close, with the VE in SVE tied together, the dot after GOT. Sold for 170 euro.
https://www.acsearch.info/search.html?id=5969778 Shatalin BD21-27, but no punctuation between PRVS MAS
https://www.acsearch.info/search.html?id=5661518 Shatalin BD31-32, but having a colon between III and D obverse.
So, I would class yours as a likely Shatalin BD21-55?
On value, many of these orts were struck weakly, unevenly, off-center. So any that are missing these problems command a premium (in addition to whichever varieties are more or less scarce). So, although yours is well struck and pretty well-preserved, the obverse is offcenter compared to the one that sold at 170.