Hmm difficult to gauge from the pics, given the usual collection of road grime over time (Unless they where from when it was installed, which I'm guessing not?) Harrop by far will know more, but what have they specifically said gives them the idea? As in it was badly "sprayed" as in paint? (Previous comment says strayed which I'm guessing is an autocorrect) The Valley plate shows a build date of October 16, and the complete engine finished in December by the code. And going by Paul comment above it fits into the timeline of when it got to Holden. Who knows how long in storage, same as the Port Melbourne plant closing in 16, but having built engines for all of MY17. My dads August 17 built SV6 has an engine built 2 weeks prior to Port Melbourne closing
I think the difficultly you could run into with the paint approach, whilst many dealers and wreckers Aus side seem to be breathing direct from the exhaust with LS3 prices (Priced like they are made from unobtanium and powered by angle tears), it really is a bog standard American V8 (Though a great one!)
And with that, given its extensive use in Camaros and Corvettes, as well as god knows how many crate engines, its just mass produced in the same way as the HFV6 engines are, so the finish on them is going to be acceptable as opposed to perfect. Silao certainly wouldn't have the same standards as their Wixom Performance build centre (LS9 and LT6 production)
Im happy to be wrong, but unless you can actually peel off the resprayed paint, id wager that's the standard finish. The white marks seem to be the usual aluminium oxide coating that AL gets when exposed to air and water, and the finish looks the same on the aluminium bits as the LFX. Is there any noticeable peeling? That would give a pretty solid indication of a re-spray. I remember seeing a post once about a persons brand new Motorsport, and it came from the dealer with completely rusted (surface) headers, which Holden said is normal (Which it is, but id still be mega annoyed...)
Still only Holden is going to know, so youll probably have to keep hounding them for more info, and if they are cagey about it well they must be hiding something