Correct, the smaller hole is already the adequate size for the 4-40 threading to get tapped in.
Considering this part was likely made for pickups at ILM in California- the threading is sensibly imperial. Roy has a pan head screw on his replica but I have a flat head on my assembly (it has a little more clearance)
The location is verified correct- just slightly left of center and low (looking from the back) having compared the shots from Battle for Endor.
The most important aspect of recreating this is cutting off the lip and threads of the atomizer which puts everything in the right position and reveals the necessary brass highlights from underneath.
Not all matrices are made the same however, so in some cases height may be an issue on the knurled parts.
On past assemblies I have adjusted some of the vintage matrices’ threaded sections to help- but: The correct found matrix used matches all aspects.
Important note on 152s
There is an old (er) version and a new(er) version with the round head.
There are 3 things which can be different- the stamping may either say 152, or N
o152.
The band around the sprayer tubes may be crimped, or pinched tightly without the crimp.
The sprayer bulb attachment can have a squared off lip, or rounded lip.
I can’t determine for sure from the photos which of these features actually exist on the prop itself. But…
View attachment 1899677
My best guess is that it is ‘probably’ the older* rounded bulb attachment… which would be sensible if it were from the same age/place as the matrix.