I don't have answer to your question Frost but may I make a suggestion?
Go to the H&R site and click contact then send your question to them via email. H&R is a good company and they will respond quickly.
Here is a link to their site.
Also may I be so bold to suggest do the same with Cabelas as they are a major for both brands and would LOVE to sell you add-ons for the firearms they sell. After all, they make more margin on accessories than on firearms.
Please post what you find out as I am sure others have similar questions as you.