Don't let the size put you off testing that paddle. It was common enough for a thin slither of coticule 3-5mm to be glued into a paddle. You will never be able to remove the stone from the paddle but it might have enough meat to be lapped up and use-able. It looks to be a little on the small side for surface area but again that isn't a problem for razors. You won't know unless you test it.
It would also excel as a travel hone. You could do light repair on slurry, and edge touch up without needing to fill your luggage with loads of rocks. Lot's of people have and use them just for this. The only advice is learn the rock first, So you know how it works and what you need to be doing before you go on your holidays!
If you want knowledge then there are a few good sources one that helped me an awful lot was written by Mr Henk Bos. He is much loved on the forums and for his contributions to the community. He unfortunately passed away in 2014, but his family keep his archive of information available. There are 4 parts written about hones and rocks.
https://bosq.home.xs4all.nl/