I plan on purchasing these. However, I am not sure if they are 656s or 653s. While they aren't stamped "Marchal 653" on the outside, they do have a black ink stamp that says "653" and then "1379 " and the glass is marked "IGM 1642 PN". They use an H2 55W bulb, which I haven't seen in either a 653 or a 656 previously. Also, there is a date stamp, which I believe is 02 October 1967.
Another curiosity is the bottom has two metal areas that have been molded on the lip of the front bezel for easy removal. While the pair of 653s that I already own have a single molded area that comes to a point.
All I know is that I really don't know what they are.
