I'm going to toss out the guess of "Yeah, you'll be ok". However I'd back everything up just to be sure. Being sda1 you likely don't have scsi drives in your desktop (assuming you are a home user) so right off the bat special device (sd) is telling me it's not partitioning your HD. Second, I can't imaging you being the first person to have this, and I'm sure it'd be a huge issue that would be immediately resolved it did indeed mess with your existing partitions. Furthermore, it's a guest OS, there should be no actual change to anything, that's what VMWare is all about.
Lastly, if you are truly concerned (and are still waiting
1. backup your data first OR
2. Toss an email at VMware and ask em. I'm sure they'll be happy to provide some answers/insight on this and more.