Well, after waiting for someone else to chime in with true knowledge, I'll take a guess.

It looks to me as if the offset point was originally a 90 degree bend, making it some sort of marking or radius cutting tool. Can't tell from the one photo if the adjustable piece has a point or was sharpened to a cutting edge.

I guess either a harness/saddle making tool or maybe for marking holes for barrel bungs.

Could be there was more to it on the bent end which got lost/broken and someone ground it to a point. Could be one of those patented "better ideas" that really wasn't and so lost to obscurity...

If you don't get a better response and you really want to dig into it, you might contact these people.