You may want to see if you can get your barrel nut off before you purchase anything. I Googled “Sig Tread barrel nut removal“. Most threads didn’t have an answer and ended with frustration. The only one I saw that did have answers was on Sig’s own forums.
Based on the thread titled “Tread Barrel Nut”, it looks like you’ll likely need to purchase an armorers tool such as the Midwest Industries barrel nut wrench and grind away one of the three prongs to create a two pronged tool for Sig’s unique tooth pattern on the barrel nut. The poster mentions leaving the prongs at 90 & 270 degrees.
One post in that thread also mentions that a gunsmith found that Sig used Red Loctite (or equivalent) to hold the barrel nut on. The gunsmith had to use heat to remove the nut. Sample size of one there, so please don’t take a torch to your barrel on my limited research unless you’ve exhausted all other options first.
Edit: One potential silver lining is that of the people who succeeded, nobody mentioned having trouble using the barrel nut of their replacement handguard. Although their silence on the topic doesn’t necessarily guarantee compatibility.