Not only do the previously mentioned differences exist they are also at different heights. My Shopsmith was purchased in early 1987 and has the table on the left. I bought an extra table on eBay and it is the table on the right. If I use the newer table to extend the width of my main table the height is different by about 3/32”. The newer table is lower so my crosscut sled rocks.
It would be difficult to get the 520 rails to line up with different tables, for certain they have to all be the same style. Thanks for the input, it is very easy to get a mismatch set of tables on ebay; quite often the seller does't know what it is they are selling.
The middle hole on the 'main' worktable is in a different location on the two versions.
The rail tube thickness is different. I believe the elevation differences are due to the rail tube thickness.
The most obvious visual indicator is the holes in the front face of the rails that provide access to the mounting screws.
The 'left' one in the pix above is the earlier version.
╔═══╗
╟JPG ╢
╚═══╝
Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange