wrong kind of nails

[PoorOwner]

I had a landscape contractor (not fence specific) built my fence as a part of a big landscape project, he used pressure treated fir posts and rails, the pickets are redwood but I think wrong type of nail is used, not hot dip galvinized, because there is quite a bit of rust on the nail head just after a year.. Is hot dip galvinized really dull grey in color? The nails used seems like pure iron nails (do they even sell them now?)

I know this really shorten the life of the fence as the nails could possibly fail from rust, caused both by acid from the redwood and PT wood, but I want to know how I can help the situation short of replacing all the nails or pickets..

I am going to clean and stain the fence next week. I am wondering if I should counter sink the nail holes, seal it with something to slow down rust and then use a wood filler before staining?

Thanks in advance!