Found an old pepsi CO2 regulator

I was in an old warehouse and came across an old Pepsi soda machine. I looked around and found a couple regulators still attached, including the attached picture of this dual gauge regulator. No one had a problem with me taking it, as the machine was scrapped anyway.

Now, I have no way of knowing how old this regulator is, but it is safe to say it has not been in use for over 10 years, but was still working just fine when the machine was retired.

I have a few questions:
It looks kinda dirty, how do I clean it?
How do I know if it still works? There are 2 brewing stores near me, would they be able to help me out with this?
What is the average life span of these kind of regulators? It looks pretty solidly made...
Can/Should I use this to keg? I currently bottle, but if I am going to chance into finding a free regulator.. I just might have to take that as a sign to switch over!

It looks like my Cornelius brand regulators that were once owned by Pepsi. They work great. It probably works fine too, but if not it can be repaired.
http://www.midwestsupplies.com/cornelius-regulator-repair-kit.html

It is a Cornelius regulator. It should probably work fine. Just use a new washer to connect to the co2 tank and you should be fine.