Geeze, you guys I am glad you cleared up the "japan" thing! I thought I had learned what the 'japan' was from Billy!!! Oh well! Now, we all know!
Crewsemj, I see that Cathy and Pat answered some of your questions on the number following the model number - like the 15, and 201's. Here is what I think I know about the 66!
Class 66 - from 1902 to 1956
66-1 Egyptian 1902 - 06 Scroll 1906 - 1923 had back clamping feet - treadles
66-3 Hand crank back clamping
66-4 1923 - side clamping
66-5 side clamping hand crank
66-6 1921 - 31 side clamping electric
66-8 side clamping
66-13 side clamping 1920 -
66- 14 side clamping with reverse
66- 14 thru 66 - 24 reverse and side clamping
Remember the 66 is a full sized version of the 99.
This information I got I believe from ISMACS, anyway it is not always true as I did a study of a lot of our machines here in this shop. There are a few people who own a 66 that should be a back clamp that is a side clamp. I know a lot of people changed them out because it is easier to get the side clamping attachments, but there are lots of exceptions to this list! So once, you think you have it figured out - you will probably find an exception!
Nancy