Van's Auto has a new sending unit for a 59 Dodge for $80. Check it out...
Sending unit Stud Type 5/16" Mopar 1957 - 1959
They may also have a replacement trunk lock. If not, I or someone else on the list may have one.
Legendary is the best and the standard. I used them for my 71 Gran Coupe. I cannot comment on Newstalgia Parts, as I have never seen their products. Does your 4dr have the convex or concave rear window?