See scan. Never Hinged.  PLEASE NOTE: SG 590 is listed as perf 13-14 by 13 1/2. SG 590c is listed as perf 14 by 13 1/2.

This block is definitely perf 13 3/4 X 13 1/2. Based on Gibbons it should be SG 590.

The reason I want to bring this up is the big price difference between the 2 varieties and I am not an expert in this issue.

Pricing is based on the item being SG 590.