Need some help with value: 1981 Mongoose Supergoose

[Jay81]

I know nothing about vintage bmx bikes, I'm into the old balloon tire tank bikes. But I have a guy offering to trade me this 1981 Mongoose Supergoose for some Schwinn B6 parts. I would likely resell this if I do the trade, but don't have the slightest idea what this thing is worth. I know some vintage bmx are valuable and others aren't, but they all look about the same to me. Please help!
Below are the pics he sent, and I would be getting the complete bike as shown. The frame pics are when he had it apart to clean it up.

 

[mongeese]

Start convo and leave your phone number.

 

[Joe Buffardi]

Great bike!

 

[freddy]

PM SENT

 

[1979-4ever]

Did you make the trade? I was wondering how it worked out for you. Hit me up if you still need an opinion on frame, frameset or complete.