I think that should work but it's hard to say...
I assume that you then clamp the bed guard between two mattresses, so it doesn't stick out so much if the mattress is very high.
Under the heading "Specifications" there is a link to the manufacturer's page and instructions for use. Take a look at these and you will be able to judge a little better whether it works with your bed.

Hello

If I can help. We ordered this for our daughter's box bed and unfortunately it doesn't work. Had to return it

I can recommend this:
reer Sleep'n Keep XL (plastic)

The very best, hadn't found any other and this one fits and is high enough even with a very high mattress and you can adjust the fastening.