You can easily put a rubber O ring to lock the safety in the off position or you can get into the receiver to tighten down a screw that locks it in place. And there is the previously mentioned replacement part. I use the O ring. Mark
I don't believe that Marlin ever made the Model 1895 45-70 with a full length magazine tube. If the cross block safety is an issue, then simply install a rubber "O" ring on the safety button and be done with it.
The Marlin version of the cross block safety is hardly noticeable. It's not at all like the "Moon Crater" version that Winchester put on their lever action model 94.
I bought one when they were re-introduced. I could not swear to it, but I don't think they had anything but the half length tube. I had to order mine and that was all that was offered at the time.
I have a Browning 1886 high grade which in my head was a saddle ring carbine. I dug it out of the safe and it turns out to be a full length magazine rifle with a saddle ring. It holds 7 45-70s.
<Bruce Willis>
Yippee kaiyay, mf!
</Bruce Willis>
Still looking for that stainless Marlin safety plug if anyone knows.