yes, the grips used right after the ones in the beginning that were "red eagle" early ones had a 'satin' brushed finish on the silver background and I believe as Chad had noted were made from butaprene rubber,, until around 1968 but they still came on some guns for years later ( parts bin theory???)..the number 10 you noted on the panel back side was for the mold lot , started around mid 1963, again per Chad (RENE) and is found in his Encyclopedia of Ruger 1949-1991) ....note the bottom hole on the left panel is closer to the bottom of the grip panels and the right side is higher, this denotes the A-54 grip frame, early one, then they reversed this, moved the holes for the A-100 grip frame....nice grips and take care of them, they can and will "warp" when NOT mounted on the gun, one reason they went away from the use of "rubber", then hardened it, ( Plasticised) then actually made them plastic and you will see the hollowed out molded backside...nice early grips