Reccomend looking at the parts listings at Gunbroker.com. Also periodicals such as "The Gun List" and Shotgun News. The Liege model is not often found, and a forearm can be difficult. Its possible that an early Citori forearm could be fitted and something to check out. Also try the Gun Parts Corporation on line.
Try MidWest Gun Works
Check the receiver, barrel, under the forearm
Try MidWest Gun works or egunparts
Try e-gunparts.com or MidWest Gun Works.
You can find them on eBay periodically and at Gunbroker.com. also Midwest at the related link listed below.
gun shop, gun show, pawn shop, want ad.
You will have to call Browning to find out.
Browning has sn data on their website under customer service.
Check under the forearm
barrel, butt, receiver, under forearm.
You must call Browning to find out.
On the webste for Browning firearms, under customer service.