The serial number is high enough that it is definately a level 7. The earlier valves had a clip in the front to keep the powertube section of the valve from separating from the front chamber.
The extra holes in the valve back compensated for the fact that the hole in the front did not line up with the hole in the back and it supposedly affected the recharge rate. In reallity you didn't need all six holes. You only needed 1 that lined up with the one in the front half of the valve.
Your gun looks like a level 7 gun around late 1993 or early 1994 vintage with the standard feed body. It looks like you have a carbon fiber grip frame as well. For comparison purposes, I have an earlier 1993 vintage level 7 with the powerfeed and my serial number is 88**. Mine also had the earlier aluminum grip frame.
As for upgrades, if you are going to run CO2, definately consider a Palmers stabilizer or at least an expansion chamber. A level 10 bolt is always nice to prevent chops when you get into a pickle on the field and your addrenaline causes you to shoot too fast.
If you do consider a level 10 bolt, get a new regulator pison as well. The older ones released pressure at a lower value than the newer ones, and due to the higher required operating pressure of the level 10, may not allow your mag to get up to the proper velocity. Putting a retro valve on-off assembly in your valve will cut your trigger pull force from 8lbs to 4lbs, which is always nice. Get the newer plastic nubbins for your barrel. They work better than the older metal ones.
And, because you have a mag, all you really need to do to get your gun on the field, is to give it a good cleaning. You will probably have to replace your regulator seat oring, but other than that, I'll bet it works fine, even with the old orings. That being said, I'd replace all the orings just because of the age and how long they have been sitting. That'll make sure you are starting with a new gun essentially.