Does LSI *require* you to use their cover templates?

...Or can I provide my own cover, already designed in every detail, in .pdf form? (their site is unclear about this, and I hoped someone here might know)

I have a book in two .pdf files--interior pages and cover--and it's worked gorgeously for 3000+ self-published copies sold so far. I'd like to take my business to LSI for better distrbution, though, if I can just give them the same two files and get the same perfect product back from them, plus lower printing costs and automatic ordering.

Thanks in advance!

Thanks! I'll be sure to check the paper weight to compare, and if they're different to use the spine width calculator.

I appreciate everyone's helpful replies! Between this and my correspondence with LSI, I found that the answer is exactly what I hoped: yes I CAN use my own cover, as long as it's rendered in the proper .pdf format and the bar code works properly. Aaron Shepards' blog was also very helpful--that's for that tip!--and helped me know exactly what questions to ask LSI.