The bash guard is removable, the two smaller rings are removable, the largest ring is not removable. Unless this is very cheap, I think you can find a better vintage crankset on ebay for a fair price.

edit: As an example: Crankset

It's in pretty nice shape. No idea if the cranks work with your bottom bracket or chain line, but this would be a fine crankset. Especially since it comes with a 39t ring, which, in my opinion, is good for gravel grinding assuming that you're planning on using a single front chainring.