No prob on the questions. The following is a basic history on Floquil/Polly-S paints and Fett's helmet/armor:
For many years, Fett hobbyists used either custom mixed paints, Walmart/Rustoleum/Krylon spray paints, or a combination of both to paint their Fett armor and helmets.
Rogue Studios, however, had a hunch that the suit colors were just "straight out of the jar" colors that were weathered. While speaking with a prominent ILM model maker, RS asked what paints would the ILM prop builders have used on Fett's costume. And the ILM model maker said it had to be Floquil/Polly-S paints. Fortunately, RS was already familiar with those paints because of his extensive experience with studio scale models.
After researching Floquil/ Polly-S paints that were applicable to Fett, RS posted a work in progress color list that exclusively featured Floquil/Polly-S paints. It didn't take long to realize that many of the suggested Floquil/Polly-S colors were the closest colors to the original colors that we had seen- right out of the jar to boot.
Several months after his intial post, RS had the opportunity--thanks to the generosity of a mutual friend-- to ask Joe Johnston, the original painter and designer of the costume, a few paint questions. Johnston stated that he used only Floquil/Polly-S railroad paints to paint the armor and helmet. With the paint brand confirmed and two board members picking Panzer Olive Green from a swatch card while next to the actual helmet, the case for it being the correct color was compelling.
So unless Anita's paint and Dusty Green were available in 1978-79, when the ESB helmet was painted, it's impossible in the most absolute sense for that to be the correct color. That goes for just about any other paint that wasn't available back then and that wasn't used in the industry. Panzer Olive Green is a Floquil color, which was confirmed as the paint of choice for ILMers and Joe Johnston, and it was available in at the right time.
The ESB helmet in the SE shots is the same helmet that was used in ESB. The helmet has not been repainted or reweathered. It does have some additional scratches, caused by peeling paint, and dirt and grime, caused by poor handling and storage. But the base colors remain the same as they were in 1978. Photographic stills taken on set are very deceiving. Trust me, you arent alone. I know many of us struggled to adjust our perception of the helmet after we had natural shots of the suit and helmet to contrast the flashed-out tour photos.
Below is a progress picture of one of the first, if not the first Fett helmet RS painted. Notice that it is a dark photo and Panzer Olive green looks pretty light and "right" in the photo.
Naturally, you are free you use whatever color you'd like on your helmet. It's not uncommon that some individuals prefer an idealized look or "post-processed" look for their suit. But you seemed interested in the facts and true history of how the real prop was painted, and if that is what you are after Floquil/Polly-S is the way to go.