Not normal Troy Bilt

I have a Troy-Bilt/Briggs Stratton 3250/3500 generator – model # 030378 Serial # 1015494054. I believe the engine is a B&S Series 900, but the only visible markings (without removing engine from the frame) is a sticker affixed to the underside of the engine. The sticker has two barcodes. The top one looks similar to a 12-digit UPC: 1210120116B8 - (Notice a B not a 3 nor an 8)
The lower is 13 digits:  0711918813216
This is not a normal 030378 as it does not have the normal air filter. Instead, it has some sort of a plastic plenum (intake resonator?) attached to the carburetor. This looks to be Briggs manufacture part  - It has the crank case vent, but I am not sure about this.  I would like to identify the specific engine as the plastic choke arm is broken off behind this plenum and is a bit hard to reach – I found especially so on cold, dark, snowy nights.
This generator is only used for power outages. If this ‘plenum’ is not supposed to be there should I find parts to go back to normal or go by the “If it aint broke don’t fix it”.
So, help on engine ID and/or how fix choke arm along with filter suggestions.  Will see if I can attach photo.

Here's the entire generator:
https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/generac/united-states/portable-generators/3-100-to-3-300-watt/030378-0-3-250-watt-briggs-stratton/main-unit 
 
The filter assembly should look like this:
 
 
A metal, stamped plate that attaches to the carb intake with 2 7/16's nut's.
The filter then goes in with a plastic cover, two 5/16's screws on each side.  
 
Some have a plastic, roundish end, then kinda long part that snaps into the base.
That's normal and if its there leave it.  It directs crankcase fumes (the vent tube), 
to be sucked back into the carb (EPA)...
 
.
 
 
 
The air filter assembly should look like this (a different engin

Here's your choke lever, part 109a.   There are some slightly different style levers (all 109's),
so match up what you have to the below link..
 
https://www.partstree.com/models/121012-0116-b8-briggs-stratton-horizontal-engine/carburetor-3/
 
You have to gently pull out the butterfly, pull the plastic what's left of the choke out. 
Reverse procedure to assemble
 
 
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Thanks for the model information. The bar code deciphering completely escaped me. Next challenge will be what to do with the 'black box' that replaced the intake air filter system.

That style air filter assembly is VERY common... 
 
Get the correct and pitch what sounds like a home made air box..
 
 
.