We would need to know the model number and other specifications to possibly answer your question. As with any firearm, it is not possible to accurately appraise a gun without seeing it. If you have one. recommend that you see a local gun dealer for an appraisal. You can also do your own investigation by looking at other models being sold online. Try the gunbroker.com or a periodical called "The Gun List" You can also reference the Blue Book of Gun Values which can be purchased on line at various retailers.
Pretty certain you mean a Citori. If that is what you are looking at, it is a over/under trap gun.
100-800 usd
Your citori lightning is worth between 575-1,000 dollars for the grade I lightning in 60%-90% original condition.It will be worth more depending on the grade level.
Try Midwest Gun Works
Impossible to answer without an appraisal
*The Citori Special Trap has these features: *Checked Stock and Forearm Grip *Oil Finish *Right Hand Palm Swell *1" Trap Recoil Pad *Stock fits "Short Tang" trigger guard Type 3 Citori only. *Browning suggests a price of $307 but it is offered for 25% less,or about $230, by some. *This firearm should have any and all work done and all parts installed by **PROFESSIONAL GUNSMITHS ONLY! *The following is a cut and copy from Browning's Official Site: *CITORI SHOTGUNS - THE PERFECT BLEND OF BEAUTY AND PERFORMANCE *No other shotgun enjoys the reputation of the Browning Citori. The Citori has earned this respect due to a high level of craftsmanship, reliable function, regal looks and sheer performance. Action components are machined to exacting tolerances, heat-treated for greater strength and carefully fitted with the traditional lamp-black-and-file method to ensure the precise fit of critical components prior to being assembled to the action. Wood-to-metal fit is paramount on a gun of this quality and with tight, consistent junctions the Citori doesn't disappoint. It is no wonder Citori owners take great pride in their guns. Take any Citori off the rack and see the fine fit and finish. Open and shut the action. Throw it to a shoulder. Sight down the barrels. Only then will it be fully understood why the Citori has gained a reputation as the finest over and under shotgun available. *Hammer Ejectors: Browning ejectors are fired by a sharp hammer blow. This strike gives more positive ejection than the push imparted on competitors
The code after the "pm" is the model type. Are you sure it says 143? Browning doesnt list a model 143 Citori, but they did have a "153". The 153 denotes the Hunting model Grade l with a 3" chamber. According to info I found, 143 indicates a trap with a Monte Carlo stock. I do not know why Browning does not list it.
100-1000 usd
The prefix of 4M to your serial number indicates that you have a Browning standard weight model auto-5 shotgun,which was made in the year 1964.If it was a trap model,it would be so marked.
The browning superposed lightning trap shotgun will command a nice price.If your shotgun is between 60%-90% in its original finish and a good set of bores,you can get between 700-1,000 dollars.
Without a detailed description of all markings, features, box, papers, accessories, etc.. you can be in the <100 USD to >1000 USD range.
You will have to call Browning since you don't mention the serial number.