Bolt size for chain guard.

[Striker1423]

I'm going over a few things on the bike and I noticed,  aside from the dirt last year left me, I'm missing a few fasteners and rubber bits. I got a new rubber dampener for the chain guard, but the bolt for the front is long gone (On the front of the swingarm). What size bolt is it for the 73-75 RD250/350?

This thing loves rattling stuff off it lol.

[m in sc]

pretty sure its an m6x20 or 25 and has that funky d shaped washer and rubber boot