The thing about Century is that, though based in Saugus, California, they had locations scattered across the US. In addition to doing pressing and manufacturing, they also provided on-site recording (which explains the millions of school and church-based LPs). You could do as few as FIVE records (pressed and manufactured, not acetates) with the company, albeit at around $30 a pop. I have a works list where you see all of the price breaks, which pretty much annuls every dude that swears that you "can't press only ten records." I wrote an article in Wax Poetics (horror!) where I showed many stock LP covers from the Century pamphlet I have. In all they offered about 100 different images.
To the best of my knowledge, Century is still in the CD duplication business at the original location (as seen in the drawing on many Century LPs) in California.
In addition to Century, there were many other larger-than-average, regional custom plants (read: send us your tape, we'll press up your record) including QCA, Mark, Gabor and Delta.
A discography of Century product is a fruitless and impossible task.
Needed, but impossible.