SRAM AXS double to single I'm looking at a road bike with SRAM Force AXS 2x crank but would like it as 1x. I see from photos that the spider is separate from the right crank.

Are the 1x vs 2x arms and/or spiders different? 

If arms and spiders are the same, I can just replace both rings with a single 1x-specific one. If the arms are the same but the spiders differ, I have to get the 1x spider as well, and if the arms differ I have to replace the whole thing. The seller don't do any customization so I can't ask them to swap.
I haven't done it, but I am pretty sure it's doable without purchasing a new crank.
SRAM shows that switching between AXS 2x and 1x is as simple as changing the chainring: 
                
            
However, if you have AXS Wide 2x, it's 94mm BCD (vs. 107mm), so you will need both a new spider and a new chainring (AXS narrow-wide 1x chainring with 107 BCD).