Silicone bead around pre-fab shower

Installed a Sterling Ensemble Curve shower stall recently and then put greenboard around it. Following manufacturer's suggestions, I left a 1/8" gap between the greenboard and the shower edge to be filled in with silicone.

Hired a guy to do the finish work on the drywall and came home to find he'd filled in the gap with mud. I told him about Sterling's directions regarding filling the gap with silicone and he said he always muds right up to the shower edge and then runs a bead of silicone at the edge with no problems.

So, I can either just put a smooth bead of silicone on the joint like he says, or I can scrape out the mud and fill it in with silicone as recommended. I figure the latter is the best option, but just wanted to see if others follow this guy's method and have had any issues. Thanks.

The plastic in the shower walls will expand and contract at different rates than the drywall, so it will crack - silicon will stretch some to prevent that from happening. The shower door or curtain should keep moisture away from that edge, but you may not like the crack that eventually is highly likely to show up. If the expansion is more than expected, having a rigid joint might put more stress on the panels. I doubt they'd generate stress cracks, but I suppose they could. It's always best to follow the manufacturer's instructions.

Your install is a common one and may last for many trouble free years depending on the rest of the install & how it's maintained. We've installed Sterling shower units and have have good success with installs such as yours. Since it's done, I say leave it and see how it goes. If you were to try and cut back the mud & tape to create a gap for a sealant, your odds of damaging the shower surround would be high.