FGC9MKIISD sling or no sling mount upper

this the same upper just with out the sling mount on it. ow with sling mount like the original MKII upper.

what makes this a MKIISD upper? the only difference with the MKII model is that there is a space added for the bolts at the barrel retainer. this idea was taken from the FGC9 SD 
what can be found here: https://odysee.com/@c0ld_d8rk_h8nd:8/FGC-9SD-release-V2:1
but this will prevent the barrel from rotating. or give the bolts in your shaft collars more space in case those are longer then normal