With a google search on the block, I saw it's a small block:
3951511, 1970-1980 400 ci car & Truck, 2 & 4-Bolt, 3-freeze plugs
so nothing too out of the ordinary there, but the heads look the ones on my 69 Z/28. I have to look at the pictures closer to make sure. I just looked in Jerry M's 67-68 book and the double hump heads look very different in 67 & 68. In your top picture the left hand head is kind of far away but it looks like it matches my 69.
Here is a picture of my 69 Z/28 double hump heads:
and my casting/date code
For the date:
first letter= month where A is January, B is Feb, etc
middle numbers are 1-31 for day of the month
last number is year, where 8=1969 and 9=1969
so for my right side head, L218 = Dec 21st 1968
yours looks like, I168 = Sep 16th 1968
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The 186 casting heads could have been used on 3 different engines:
Year CI Intake Exhaust
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1968-69 302 2.02 1.6
1968-69 327 2.02 1.6
1970-72 350 2.02 1.6
So based on the date, the heads either went on a Z/28 DZ 302 motor or a 327 (maybe a L30).
They might be worth $$$ but I'm no expert on what they might be worth. For determining value, you could either try EBay with a high reserve number or posting a question in the Team Camaro "What's it Worth" section. Those guys sometimes give a value of 1/2 what you could get on EBay though.
Roller rockers might have been out in the 1960's but as far as I know, they were not stock:
http://www.harlandsharp.com/history.htm
According to Jerry MacNeish's book "The Definitive 1969 Camaro Z/28 - SS 396 Fact Book":
1969 302 cylinder heads were resdesigned with threaded bolt holes at each end for alternator bracket installation. The combustion chamber and valve size remained identical to earlier 302 castings (2.02-inch intake valves, 1.60 -inch exhaust valves). The 1969 302 casting number is 3927186. The double hump casting marks at each end were made smaller than the '67-'68 casting. All "186" castings installed in '69 Z/28's received pressed-in rocker arm studs. Casting numbers and date codes can be found when the valve cover is removed. The SS350 is equipped with "18" cylinder head castings, however, the valves are smaller (1.94-inch intake valves, 1.50-inch exhaust valves).