1996 orange P7 post size?

[cherrybomb]

Yup. Orange fitted shims from new on some frames for some years (if that makes sense?).

Strange though, they usually shimmed down to 27.2mm not 26.4

I reckon you may have an earlier seat post from a Clockwork with an aftermarket shim that fits the P7.

Or they could have just been using up supplies of the narrower posts I suppose.