First, it was manufactured by Stevens; they bought the rights from Browning. It could be close to 100 years old but at least 75. They sell for 100-200 dollars.
If it was manufactured prior to 1968 it probably doesn't have one.
Western Field model m5500 20 ga was manufactured by Savage Arms
Gun Digest.
This is actually a western Field gun that was made by Stevens Arms co. It is on a Browning patent, but not a Browning gun. They usually sell for $100-250 depending on condition
If you cannot easily see a serial number, then it was manufactured prior to 1968 and doesn't have one.
I don't know but I have one too with serial U116679 would like to know the age also
how old is a western field 12 gage shotgun browning patend 38535
I own a Western field 12 ga (serial no g613481) that I purchased from Montgomery Wards in 1973-4. I believe it was made by Mossberg because I have ordered a replacement stock and barrel for a Mossberg 500 that fit perfectly. Your serial no is higher, so I'm guessing it was manufactured at a later date. .
The manufacture date of western field model M782 with the serial 830424 is 2012.
I owned a 1967 Western Field Tent trailer and the one I owned was manufactured by Ajax Mfg or Welding in Iowa. Good luck in your seatch.
Stevens.
Bruin