Blake's bounty hunter gun - rubbing down

With the rubbing down of the lettering on the side of the Star wars blaster, i then copied what bill Pearson did - covered up the top where the scope used to be with Plasticard, along with the side panel that had the slots to allow the sound to come out.
I've used Go-Fasta stripes for the panels on top of that for ease.
Though i want to try and replicate as far as possible what Bill did, i've a bit of a head scratcher when it comes to the area just above the "safety catch".
At first i took it to be a case of Bill putting a piece of Plasticard, with a slot cut out as detail, over the lettering i'd just sanded off - after all, he had just a day to come up with the gun and maybe didn't have time for sanding.
But, look at the original.
If he DID add the slotted panel, then he's cut off the safety catch and then perfectly glued it back onto the new panel.
Would he have time to do that, i wonder?
So thinking its an original detail, lost when the blaster was reissued.
But, it looks like there's something going on under that slot, as if it is indeed covering up a lower layer.
So what's going on?
No idea.
Just have a quandry now - do i leave it as is? Cut off the safety catch, put in the new panel then bung it back on? Or put on a new panel that's made to go around the safety catch?