Marlin lever actions in 30-30 were not introduced until at least 1895, when the cartridge was first introduced, probably several years later. And the 1893 Marlin (the first Marlin chambered for 30-30) was not around back in 1884, mostly because it was not introduced until (let's see here, I'll figger this one out, uh, hmmm, oh yeah) 1893. I am not trying to be a smartaleck, I do restorations on old rifles. So, let's try that exercise again. OK?
Now, look at the rifle. It has a model designation on the barrel. What does it say? It has a chambering designation. What does that say? Is the barrel round or octagonal? Is the lever loop squared or rounded? Is the bolt of the rifle round or square? Also, try re-reading the serial number. It may ahve a letter in front, or it may have more than 5 digits to the number. As a last resort, post a photo of the rifle.