FWIW, the title of the thread is, "Weaver GS-2 4-8-4 so I'll address what little I know about that particular model.
The biggest problem I'm aware of is the tender. The tender is a GS-4 type and is completely incorrect for a GS-2.
As a matter of fact, I wanted to buy some of the Weaver tenders for the GS-1s I'm building but decided not to because of all the work required to get them even close to being accurate.
If you can see your way past this then I'd say get one and enjoy the value.
Jay