Gwf.E Marked side rail.

Is this Erfurt Mauser?

And are Erfurt Small Ring M98s Small or large shank thread?

Are they good or no

If I remember correctly, think I made a mental note to avoid Erfurts

Erfurts are small ring 98's with large barrel shanks. I avoid them.

If the left siderail is marked Gew 98 and has the Erfurt Crown Date on the ring it is a straight up large ring 98.

The small ring Erfurts are marked Kar 98 on the left rail. The small ring Erfurts take large ring barrels and bolts. They are great if they are hard enough. The 1918/1920 double date ones seem consistantly harder than 1916 and earlier. The receiver ring is very thin and it is hard to drill and tap the soft ones for scope bases in my experience. The lugs seem plenty strong and hard enough on them though.