Sure looks to be one of those^, so quite a mark-down from what the PO must have paid (not to mention the shipping and wait time) with just one paint chip and perhaps some minor wear from having been built up. But to my eye it looks little taller than 53cm, and I think most original San Cristobals were "square" dimensions, so the top tube would match the seat tube (this one says 55cm TT).
Will have to re-measure my OLDE San Cristobal to confirm that!
EDIT: Nope, my old San Cristobal (with the early graphics so definitely a Pelizzoli-built frame) was not "square" after all. The TT is about 2cm longer than the seat tube height (all measured C-to-C).