Need help identifying model number

Hello ladies and gentlemen,

I recently (yesterday) picked up an H&R top break chambered in 38 S&W (black powder I believe). I can't fully identify the model number or find the few parts I need to complete it. I think it only needs a rear trigger guard pin and main spring. I only paid twenty dollars for it so I'm not out much if I never get to shoot it (I do reload so ammo won't be the problem but load data may be difficult). I do want to return it to firing condition using period parts. Pieces of history need to be saved and maintained. Thank you in advance for your assistance.
One pic in pieces pre rust removal and one intact post rust removal.

Across the top strap it says "Harrington & Richardson Arms Co. Worcegt Dr Mass USA Pat Oct 4 87 May 14 & Aug 6.

Thank you for the data. I've found some period parts at Numrich and on ebay. I don't have much intention to shoot it. I just want to return it to one piece. Make it whole again. I've got a Colt lightning that Im working on too. I'll never shoot it either. Mostly because the barrel is shot out and it's chambered in 22 long not LR. I'd like to keep to original parts in the H&R but identifying which parts are correct is difficult. Jim you say it's an automatic ejection model. That helps immensely. The ejection action does not function so I know that I need more than a mainspring. I do reload so if I were to try and shoot it I'd replicate factory black powder ammo and reduce staring load by 10%. Thank you again