In theory, yes, in practice, no (or at least your results may vary). VS is designed for side-by-side installations. For consultants, very often there are several versions of VS installed to suit the client environment.
As they say, RC is pre-software and bugs are expected. No one can guarantee that you will not have a problem. VS is a huge and complex code base. Throw the number of permutations of possible plugins and extensions, as well as environmental conditions, and there is always a chance to break. Just because it did not explode on someone else's system does not mean that you will not have problems.
When I installed VS 2015 CTP6 few months ago, it broke the VS 2013 installation on the same computer. VS 2015 CTP6 installed without errors, but trying to "log in" (Microsoft's new annoying way to infect all software with a user's login) hung and became unresponsive. After rebooting, devenv.exe complained about corrupted user settings, and even before I tried, I had a bad feeling that VS 2013 also exploded. I was right, and it needed a reinstall to work.
Now, on the other hand, I installed VS 2015 RC side by side on a machine with VS 2010, 2012 and 2013 without any problems. Does this mean that you will not have a problem? Of course not. This is a preview version. If this is a critical machine and you don’t have time to spend several hours reinstalling VS 2013, I would install it in VM . If this is not critical or you have time to reinstall, if necessary, roll the bones. Honestly, you should be okay, RC is pretty stable, but you never know.