I had to change a shut off on my water heater from a wrench type black pipe shut off to a simple half turn shut. The shut off is brass. Are there any known issues with brass to black pipe (is that iron) connections or metals?
Also I used TFE paste. Is that cool with gas (brass & black pipe)?
A brass valve will be fine IF it is rated for gas. Same for the pipe dope...if it is rated for use with gas, it should be fine.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013