Vsa means it is a telephone equipment, wdst signifies it is a wall telephone and 38 it’s type number. This model may have various type numbers, depending on the electronics, handset, cord, etc.
Please see also the earlier A2 version, I have.
When I bought this specimen in 2017 it did have the wrong type of handset and dial. I replaced those, but I am not 100% sure this is the exact model handset that was original to this telephone, as various types were used at the time.
I did replace the NrS 38 dial with a V.Sa. sch. 90 A2, correct for this model so at least it looks like it is from 1930 again.
It has a V.Sa. MS 54 T 25 diagram, with an extra spool, compared to that a2 version.
Date stamp on the back indicates it was made in 1930.
Most sprecial about it is that is has the Dutch coat of arms on the side, indicating it was once made for the Rijks Telefoondienst. Telephones with such a decal are rare and sought after.
Please note that the A2 1929 version does not have the orange lettering on the back, but instead the type and serial number stamped in.