Wow! First let me say too bad it's not all original because even though it probaly is a 74-75, I believe it would be considered quite rare, a lefty SG standard, no crown inlay on the headstock and I believe it may have had factory mini-humbuckers, I searched around today and found a listing for a 70-73 w/mini-buckers and seeing that yours has one and you said the bridge p/u wouldn't go down far enough, I just wonder if it didn't originally have the minis, the smaller pickguard was standard on alot of SG's, but the lack of the crown inlay is kind of strange on a Standard, someone must have stripped the cherry finish because it wouldn't be under the pickguard and in the control cavity if it was factory tobbacco, you probaly know all this already but I'm obessed with this right now and would love to see it in person, definitely get rid of those yellow jumpers, the pots should all be grounded by the foil the only ground needed should be to the ring connection on the output jack, Good Luck Benoit