The following are the courses listed in Golfweek's Top 200 both classic and modern that were opened within the "dark ages" timeperiod as defined by Ran (1949-1985):
Lancaster CC, 1959
NCR CC (South), 1954
Deepdale GC, 1956
Laurel Valley, 1959
Dunes G&BC, 1949
Champions (Cypress Creek), 1959
Point O'Woods, 1958
Saucon Valley (Grace), 1957
Shady Oaks, 1958
Torrey Pines (South), 1957
CC of Florida, 1956
Bayonet GC, 1954
Pauma Valley CC, 1959
The Golf Club, 1967
Muirfield Village, 1974
Spyglass Hill, 1966
Honors Course, 1983
TPC Sawgrass, 1981
Castle Pines GC, 1981
Desert Forest GC, 1962
Harbour Town, 1970
Oak Tree, 1975
Butler National, 1974
Long Cove, 1982
Eugene CC, 1967
Crooked Stick, 1966
Jupiter Hills CC, 1970
Hazeltine National, 1962
Shoal Creek, 1976
Saucon Valley (Weyhill), 1969
Cog Hill 4, 1964
Atlanta Athletic Club, 167
Grandfather, 168
Stanwich, 1962
Greenville CC, 1970
Pine Tree GC, 1962
Mauna Kea, 1966
Bidermann GC, 1965
Desert Highlands, 1984
Tamarron, 1975
For what it's worth, GW lists Firestone South as 1929, meaning they don't consider it wholly a part of the time period. Even if it were, to me Firestone South doesn't touch several other RTJ layouts. And as you can see from the list above, even if you remove Dye and Nicklaus courses that perhaps shouldn't be considered "dark ages" despite their year of opening, there's still plenty of competition.