You have a lovely machine and a nice compact cabinet to go with.
DH and I had a similar experience getting his 403A. She was being used as a display table in a stall at an antique mall. I also reached under and felt cold metal. Since she had stuff piled on top, I got down and peaked and could see it was a 400 series. Since my husband had just passed up a 403A in another shop that was for sale at $125 - I called him over. We cleaned the table off and opened her up - and saw a nice 403A. DH paid $35 for her, no "extras" but she was still worth the price.