I'm looking to get one of these for a newly acquired A4 and plan on keeping the standard handguards however I'm planning on putting an IT/Streamlight M3 light mount on them and according to this pic the sling will intefere with this.  

My question is: Is there a model that utilizes a front side mount sling swivel and if so, what's the code?

Also, I'd seen an ad in a Guns and Weapons of LE advertising a Specter universal sling that was able to be used on M4s, A4s, A2s, etc.  Which model is that?

I realize I should probably just email the party with the above site but hoped I could get some insight here first.

I guess it helps to be thorough, at the very bottom of the page is the Universal model.  Does anyone have experiences they'd care to share?

Thanks,
Scott