Mike,
(To catch everyone up, I ask the question why San Juan Coach # 325 was different from the rest a while ago with no results.)
I found at least one difference on Coach 325. Not a big one mind you but...
Look at the Needlebeams. Coach 310 and 325 do not have pillow block material for the truss rods but have queen posts. They look like they have the "X" braces between the queen post as well.
I'll keep looking and let everyone know if I find something else.
272 Minor Difference
310 Major Difference
312 "Standard"
319 Major Difference
323 "Standard"
325 Minor Difference
326 "Standard"
327 "Standard"
Kevin (The picker of the nit) Cook