The Marlin Model 336 mostly takes after the Winchester 1873/Repeater 1874 in terms of stats.

Damage on the Marlin is the same as the Repeater 1874 at a base of 246, increased to 258 with the 5% perk deck bonus. This one shot headshots most common mooks on all difficulties with 0 skill investment.

Accuracy on the Model 336 is fantastic at a base of 84 and can easily hit 100 Accuracy with minimal investment.

stability is a dump stat on lever actions, who cares lol

Concealment is the same as the Winchester 1874 at 12, but you can get some ... questionable ... attachments that will bump your concealment back up to match the Marlin 1895, albeit at a cost to accuracy and damage.

The fire rate is technically higher than the 1873 at 90 RPM compared to the 86 of the 1873, but I doubt you will notice this advantage and can count them as the same for all purposes. To keep the Model 336 in check compared to the Rangehitter, the fast firing lever doesnt speed up your fire rate, as you would just end up with a practically superior Rangehitter if I gave the levers their fire rate increase. Therefore, the levers are purely cosmetic options.

Modularity is as you expect from MW2022, with the exception of the ability to add muzzle devices. I am not really sure what having muzzle devices would add, as your accuracy is already perfect, stability is a dump stat, and you have the suppressed barrel if you want a silent lever action.

The noticeable downside of the Model 336 is its ammo, or lack thereof.

Your tube capacity is the lowest of all the lever actions at 6 rounds at base, with options of 4 or 8 rounds depending on the barrel used.
Your total ammo capacity is 4 tubes' worth of ammo, or 24 rounds carried.
Your ammo pickup rate is noticeably lower than most other manual operated sniper rifles at 1.5 minimum/2.6 maximum. With the Walk in Closet, you have a pickup rate of 2-3.5, which is still noticeably lower than most other 256 damage sniper rifles.

Fortunately, the ammo shouldnt be too big of an issue if your aim is true. Aim well and prove why the cops should fear a vaquero who only needs one gun.