If you just replace the blade carrier on the WGOS sight with the ghost ring carrier and leave the sight mounted mid barrel, you won't need a higher front sight. The WGRS sight is mounted in the two rear scope mounting holes which puts it much higher than a barrel mounted sight, that's why they said you'd need a higher front sight for it to work, the ghost ring aperture isn't a WGRS sight, just an option, the WGOS sight comes on the Talo rifles, the base of the WGOS and WGRS is the same AFAIK tho, I've not compared them.
Tim