You could try here, they bought the stock that IPB had when Gene bought the remaining parts on Alvin G's closure. This is just a straight search using "Alvin G"....

http://www.pinballspareparts.com.au/catalogsearch/result/?q=alvin+g

...a more thorough search might locate the parts you need.

Congrats on picking up the game. It's a nice little rarity. Which cabinet version do you have? Even though there were only 103 of these made they still managed to have 2 different setups.... some with the start button on the left and the ticket dispenser on the upper right, and some with the start button on the right and the ticket dispenser on the lower right. If you wouldn't mind, please let me know the serial number so I can add it to my Alvin G log book. Thanks!

On to your question here.... Unfortunately, most flipper parts are basically impossible to find. Coils, bats, and bushings can still be found here and there, but plunger/links, pawls, base plates, and coil stops are NLA unless someone digs some up in a parts stash. (The LAP-002 plungers out there are not for flippers!) Since you're just needing the plunger/links though, you can get by with a Williams A-15847 or A-10656 plunger/link. The link will have to be modified a bit for it to work, but all it will require is that you need to sand down the link just a tiny bit to make it thin enough to sit on the pawl and get the e-clip on. Shoot me a PM if you have any questions on this.

You could always convert to Gottlieb flipper assemblies.

Sure could, and they are the most similar. A lot of people even swap them out for B/W mechs, but I always try to keep as many original parts in these games as possible. It just preserves the original feel and seems right to me I guess....

If anyone out there reading this does swap any of their Alvin G flipper mechs out please let me know and I'll be glad to take all the old usable parts off your hands. Very seldom is everything trashed.