Can you tell a Fender P from A Squier P
 

Other than the obvious - the name on the headstock. Is there a quick way to tell a Fender Bass from a Squier? I have seen for sale listings where it is not clear. Sometimes I see photos, with no view of the headstock and I cannot tell without a conversation with the one posting. Even then I don't always feel like I get a straight answer. If I go to have a look, what is the first thing I should look at - in case the head has a decal or something that makes it unclear. Is there a different number of screws on the pick guard or some other tell tale sign?
Thanks for any tips.

Until recently, Squiers have used inferior hardware on most of their instruments. Most notably, the bridge and tuners.

Also, something that is easily changed and I'm not sure how it's been through their history, but my squier has round top knobs with no set screw, where my fender has flat top knobs with a set screw. Both are new. Squier is a Matt Freeman p bass and the fender is the American special p bass in honey burst. Maybe someone else can chime in on whether or not this is usually the case.

It depends on the model and how closely you look at the bass.
I own a Squier Matt Freeman, an AVRI 57P and an AS Jazz.
The bridges are all different. The Squier has the high mass they've been using on the CV series. The Jazz has the US string through high mass bridge and the AVRI P has the bent plate with the threaded saddles.
As already stated the control knobs on the Squier are pressure fit and the Fender models have set screws. The knobs themselves feel like they are higher quality on the Fenders. The Squiers seem like the metal used was poured into a mould. The Fenders look to be machined metal. (fwiw)
The scratch plate on Squiers can be cheaper material too, with some warping. My Freeman pickguard is a bit wobbly. I had a VM Telebass in the past and it also had a PG like that. 3ply black and not totally flat. Fenders have always been flat. My Jazz PG is flat and in the past I've had an AS P and a Hwy1 P and both had flat PG. Nit picky I know.
The neck plates are different too. If I remember correctly, my Squier has "Squier" scribed into it. I think the AS Jazz has "Corona, Calif" on it and the AVRI has the serial# punched into it.
Some people think the frets are rough on Squiers compared to Fenders but i can't really tell. Maybe very slightly. The neck on my AVRI feels amazing and the AS Fender is really nice too. Squier is nice but maybe a bit less nice compared to the Fenders (if that's possible). AVRI neck is gloss nitro, the AS Jass is satin poly and the MF Squier is glossy poly.
Tuners can be different also depending on the model.