Scott 1581c, 1582B Paper Varieties

I have a couple of questions about these two stamps. The questions have arisen from slight discrepancies between my Scott 2011 Specialized and the spaces provided on my White Ace pages:

According to Scott, 1581c (Americana Series, 1c Inkwell) was issued in 1977, but White Ace has a space for it (labeled "white paper") on a 1981 page. I would tend to put more weight on Scott's date, but White Ace has a space for 1582b (American Series, Speaker's Rostrum) on the same 1981 page, and 1582b was issued in 1981. Is there a reliable source to confirm 1581c's correct issue date?

As for 1582b (Americana Series, 2c Speaker's Rostrum), Scott lists it as "cream paper" whereas White Ace labels its space "white paper." So once again, is there a reliable source that can confirm which paper type is correct for 1582b?

Incidentally, Scott's value for 1582b cream paper variety is the same as the greenish paper 1582. But Scott doesn't list a value for 1581c. Is it extremely rare?

If someone could shed some light on any of this I would greatly appreciate it?