Loaded question. Depends on many variables. Biggest one being how bad one wants it. I know this doesn't help so I'll at least say that IMO if it's less than $800 you got a sweet deal. High side depends on the buyers desire.
I love my 444XLR. Does it have a scope on it? If so add for that and it may be well within the value of it....They are not making any more JM XLR's so that is a factor. If it is in good shape could be worth it to you.
For that price I would go with an SBL and get the larger lever and the XS Sights Lever Rail with Ghost ring. The drop in barrel length will not be noticed except easier to carry.
I would want to stay closer to $800 max cause I would add the Larger Lever and Lever Rail sight system to it.
As long as it is in excellent condition, $1000 for a 2006 1895XLR is a good buy.
In December of 2005 I went on a 4 month waiting list before I purchased mine. At that time it retailed new for $725 plus tax. That was over 8 years ago.
Two years ago, I picked up another 1895XLR manufactured in 2006, for my son. Pre-owned, but in mint condition. That rifle came with Leupold mounts, rings and scope for $1100 on GB. And I thought I had a great buy.
Since then, the JM Marlin XLRs made prior to the Remington buy out and that are also in excellent condition, are becoming an even rarer find. Thus $1000 for one today, in excellent condition, is the norm.