It looks like you have most of the basic parts to both the Model 10E and 10ER. Here is a little history for your Model 10's. Based on the serial numbers (10E S/N E-2390 and 10ER S/N 58599) they were both made in the Eastern Plant. E-2390 probably in 1948 and 58599 likely in late 1951 or 1952. When 58599 was made some serial numbers from the Eastern Plant still had the "E" prefix while others, like yours, did not.
It is nice that you have bench ends for both Model 10's and one even has the Retractable Casters. Nice to have for moving it around. As you get into disassembling both of them you will notice the difference in the parts and why some parts are interchangeable individually while others must be done as assemblies. Try to keep the parts for the 10E separate from the 10ER at least until you know the differences. Since you have 3 Tailstocks and 2 Metal Extension Tables, I believe a previous owner bought the Special Conversion Kit for the Tailstock-Extension Table. This conversion Kit replaced the original wood Extension Table and Tailstock. That Tailstock for the wood Extension Table is the one with the wing nuts. The only Rip Fence I see is the one for the Model10ER. The 10E originally would have had the Fence without a rear lock and the conversion Kit Fence would have the front lock screw straight instead of angled like the one for the 10ER. Just a small example of changes that occurred during the production of the Model 10E and 10ER.
There is some good news as it pertains to missing accessories like the Drill Chuck. The Model 10E and 10ER have the same size 5/8" diameter reverse tapered Spindle in the Quill that all Shopsmith Mark series tools have so most current Arbors, Chucks and Spindles can be used replace the original ones.
Do use caution when buying used replacement parts online. Many sellers do not know much about the Shopsmith Tools they are selling parts for and even call non-Shopsmith parts as being Shopsmith.
Lastly do you have Owner's Guides (Manuals) for both of the Model 10E and 10ER? These will be helpful in not only identifying parts using the parts diagrams and lists but also in using the Tools themselves.
If you want to learn more about the Shopsmith Model 10E and 10ER I recommend the Thread I started titled Shopsmith Model10's What When and Where that can be found at the link below.
https://forum.shopsmith.com/viewtopic.php?t=23647
In the other thread you saw a picture of a restored Model 10E which would be like yours but with the original wood Extension Table. Below is a picture of a restored Model 10ER which would be like yours. It includes the Speed Changer, Lathe Chisels and a wobble Dado Saw Blade not included as they came from the factory.
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