Is this Tri-Compax a good buy?

Diabolik

40 to max 49 style (open 6) is common on re-issue dials. The tell tale sign is the minute counter is split in 5 min not the classic 3 mins (1/20th of an hour) as the were commonly found in the 30s and 40s. Almost all very early tri-compax moon models had minute counter split in 3 (ie 0, 3 (1/20), 6 (1/10th) etc). This dial is split in 5s which points to a later (60s) reissue. Check the "dial variats" thread ...