Howdy, the 1895M came with an 18.5" barrel, some ported but most not. There were no factory 1895M's with a shorter barrel. These are "not" scarce however they are no longer manufactured. They were first made available starting in 2000 and the last one was built in North Haven in November, 2010 just before Marlin moved the factory. Remington chose to not start that line back up after the move.
You can check them out on Gun Broker however they typically run between $450-$600. I bought my 2000 model earlier this year for $450.
Best of luck,