you should be able to pop that metal clip off the bottom and swap the coupler for a better one. Or you can shave it off and swap in a body mount coupler kit.
You sure can. Use these: https://www.micro-trains.com/index.php?_route_=universal-coupler-1129-2-pr-00130013 Wolf
Nonoperating would be easy (red Caboose couplers, medium shank) would just fit in the box. That looks like a Trix, with the bodymount Rapido coupler. For Micro-trains, there were conversions that fit into the "T" shank boxes for locomotives. Most cabooses run low on coupler height, this is an offset shank style but you can see how this entire thing fits in the existing box. https://www.micro-trains.com/index.php?_route_=universal-coupler-2-pr-1128-00130012 Here's the master list that gives you the various part numbers for conversions. You need a shank like an 1128 but whether or not you need an underslung knuckle or not depends on the height from top of rail to the top of the box. Hopefully you've invested in a coupler height gauge, you really need one of those anyway.
You may have to separate the body from the chassis. That metal cover (I think) has two metal tabs crimped over the top of the coupler box. Perhaps the crimped tabs can be undone without dismantling the caboose though I doubt it. Sent from my SM-G950U using Tapatalk
I tried to separate the base from the body, but the ends won't come loose. I was afraid to pry any harder.
Do the walkways and railings on each end look to be a separate part from the body and the frame. If so, it would just be those parts that you would want to remove to access the tabs for the couplers.
To remove the end rails -- you can slide a flat blade under them and lift/twist up. The metal tabs are on top of the platform. - behind the rail/s. You don't need to remove the body -- that would make it easier -- but, not necessary. Regards, Wolf