To me,, a lot depends upon the value of the OM box. If it's a $100 box (or more) the extra to use the convenient FR boxes is fine.
But,, if you can find a different box to ship it in,, the weight will be a non-issue,, but the size may make a difference.
I often take questionable packages, filled, but not sealed, to my PO to have them check the cost of shipping before I quote a price for it all.
Example;
I just had a guy on another Forum buy a few smaller items,, & one other item that would not fit in a SM FR box,, but was too small for a medium FR box. Yet,, it was also kinda heavy. My PM weighed it, AND measured the box I was using. It went down from $15.50 for a Med FR box, to $12.80 for my odd box. Saved the guy a few bucks.
So, if expense is an issue,, find a different box to ship it in,,, but try & find one that will not be too much bigger than the OM box. (PS; If you save them, the WW shipper for a case of primers,, can be folded open, reversed, and a LOT of different Ruger OM boxes fit inside the plain brown (now) box. I use them to store my OM boxes,, and they are almost identical as the OM shipping boxes from that era.)