Just saw this. When I snagged my Squier Musicmaster bass off CL it was in rough shape. The black body was full of scratches and the white pickguard had the characteristic and common break at the output jack.
I got a nice pickguard from this place called Jeannie Custom Pickguards but can't seem to find their site. It is in black/gray pearl and it was a great and simple process. Sorry I can't give you more info on them. All I came across in search results were some complaints but no site.
That being said, I did get a couple pickguards from this place for my Fender Musicmaster. The guards are different but you can send a tracing to them for your Squier. My experience with them was also good so that's about all I can tell you.....
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Here's a photo of the pearl pickguard I got from Jeannie Pickguards, great experience buying from them, hope you have better luck finding them. It's my wife/daughter/daughter's friend playing "roadie" at one of our gigs.
This pickguard is also from Jeannie, plain white and airbrushed by my son. The bass body was done in candy apple red by "guitar paint guys"
Good luck, hope you find something.