I'm not up on 21's is the forearm original ?
It looks as though who ever did the plugs needed more practice...sadly it's on you gun. I think why they stand out so is because of a poor fit...the glue lines show.
A diamond shaped inlay wouldn't look right...because it would be touching the checkering border and would look worse than the plug.
If you initial shield the back plug it's going to look too low on the stock.
I'd get a good stock man to replace the plugs with plugs that match the wood and fit better.
