Check the bolt size it could be 4.0, 4.4.5 or 5.0 but ounce you get the bolt size correct you should be able to mount bolt pretty much any standard light you just may need to buy a bolt for $1.00 or less at a better stacked local hardware store. Also Gugies light is mounted to a demi fender/light half way the fork mount which were very common on nicer 60's bikes I which they would have kept them nice spot to mount nearly anything you want..
Last edited by zukahn1; 03-17-18 at 08:10 PM.