Customer Service at the Browning Firearms website.
Info available on Browning's site.
You can get it lettered from Browning.
The browning web site will provide this info.
Better to contact Browning at browning.com
Sorry, cant help with that limited info. Conact Browning Customer Service at link below.
Proofhouse.com has Browning sn info.
Browning contracts out engraving to many engravers.
you can find that info at proofhouse.com
MidWay USA or Brownell's Use Browning's site. Very good info.
Good rifle. Browning does histor letters if you need more info.
Browning provides histoy letters for a reasonable fee.
Please add the model of Browning shotgun you have to this info,to get the answer you seek.