thanks, Steve... the operation of the universal (Std/O) lock-on is much more apparent in your photo than in the catalog illustration. the double-sided Std gauge lock-on is very interesting (and likely rare?). and keep at your friend, that would be an invaluable aid.
seeing the print on yours, i also took a closer look at my pictures...
i can barely make it out, but it does look like it was once imprinted with "LIONEL <something>" which is now completely worn off.
frankly since my original question has be answered, feel free to post other lock-on questions or comments. the subject line is general enough.