What kind of Ram do I have?

I have a two part question regarding troubleshooting and finding parts. I have a 1986 Dodge Ram that says Custom 100 Power Ram on the side. It has 4wd.
I am not sure if it is relevent, but on the registration it is listed as "commercial". The problem specifically I have is that when it comes to parts, the categories are only for Power Ram 50, Ram 50, and w100. There is always trouble when I need a repair done or in ordering a part, with finding the "right part". Last person I spoke to said he found the part he thinks is right under "Ram 50". I am confused.
The second part is about troubleshooting. When I start the truck, I have to pump the accelerator while cranking, usually starting up on the second time. Every now and then, for no particular reason, I'll have to keep pumping the pedal to keep it going until it decides to "catch on" and stay running. And other times, while I am driving it, when I come to a stop or slowdown where I will have to accelerate, it acts like it wants to cut out and I have to keep playing/pumping the pedal to get it to accelerate. The carburetor was rebuilt about a year ago and it has had this problem both before and after and different mechanics have told me different things, with none of their ideas curing the problem. I just replaced the starter. I have used fuel system treatments which could be my imagination but I think it goes longer without problems when I do. Could it be as simple as a fuel pump or filter?

Your help is much appreciated.