All from factory shots, ie period..
52 KR tin cover, cooling scoop, no access to chain, round stamping for 10th screw, single skin all flat, no fins:
56 KRTT tin cover, flat, single skin, round stamping for 10th screw, new rib all the way encompassing chain access hole:
1958 XLR/XLC/XLCH, same XLR bike used for all the factory shots, start of elongated stamp to use on both KR and XLR:
1960 XLR tin cover, raised bit at mainshaft nut location:
1968 Rayborn's Daytona KRTT: 9 screws only tin cover, in fact late 60's CH tin cover:
1969 iron XR prototype tin cover, 10 locations but only 9 screws, that's because they reverted to 57 XL sand cores for iron XR and XLR cases, these have only 9 bosses in case.
1970 as sold iron XR tin cover, back to late CH tin cover
Patrick