I see we are hunting the same coins then
I have been paying particular attention to Constantinian types for about 15 years, but especially the variants, like campgates with windows.
an example that just sold in the latest Leu auction for 460 CHF, in nicer condition, though no windows.
Constantine I, 307/310-337. Follis (Silvered bronze, 19 mm, 3.29 g, 5 h), Rome, 318-319. CONSTANTINVS AVG Helmeted, laurate and cuirassed bust of Constantine I to the right; two stars on helmet. Rev. VIRTVS AVGG / P - R / RQ Camp gate with three turrets and closed doors. Cohen -. RIC 176. Very rare and unusually nice. Minor scratch on head, otherwise, extremely fine.