I guess you do not have anything to loose with those carbs with the blocked needles?

Drill a hole in a plug and pry it out and see what you have.

I've never done it but I've heard that some just have an orvice under the plug. At one time some models had a screw under the plug that you could adjust

I say that you have nothing to loose because a carb without two needles just will not work for model use.