not familar with that brand of struts, but can see no reason why they would not bolt right on- whether that length is correct or you bike, you would have to measure the current shocks on the bike, and then plus or minus that from 10" to see if clearance etc would be correct
10" may be too short for an older Sportster. The best way to tell is to put your bike on a bike jack, remove your shocks, and lower the jack until the tire touches the underside of the fender. Then measure the distance between the shock mounts and add whatever clearance you're comfortable with. That's the shortest you can go without other mods.
I never wanted a Harley, but I always wanted a Sportster.
If it ain't broke, don't fix it (especially if you don't know what you're doing). Most Sportster problems are owner-induced.