I think it have purpose to hold guard in place/ because rubber / but probably you don t need it with leather ... I like how you make that leather washers.....got the tang cleaned up, have dampened washers and compressed them to dry. will work on pommel tomorrow. am undecided if I should do all leather washers, or add spacers near guard and pommel. The small metal square originally on the tang at the guard (shown in pic above) came off as I was sanding. doesnt seem to serve any purpose, so I am gonna leave it off.