So I found a resin conversion add-on kit on ebay for the 1/144 HG RX-78-2 Gundam or G-3 30th ver. And you can build an FA-78-1b!
Great kit you got. If memory serves, this set also included extra parts so you have the option to build FA-78-1 or FA-78-1B. Please post pictures if you have decided to work on this.
What do you think?