  Type Ia supernovae are heavily used tools in precision cosmology, yet we
still are not certain what the progenitor systems are. General plausibility
arguments suggest there is potential for identifying double degenerate Type Ia
supernova progenitors in intermediate-age open star clusters. We present
time-resolved high-resolution spectroscopy of two white dwarfs in the field of
the open cluster NGC 6633 that had previously been identified as candidate
double degenerates in the cluster. However, three hours of continuous
observations of each candidate failed to detect any significant radial velocity
variations at the > 10 km/s level, making it highly unlikely that either white
dwarf is a double degenerate that will merge within a Hubble Time. The white
dwarf LAWDS NGC 6633 4 has a radial velocity inconsistent with cluster
membership at the 2.5 sigma level, while the radial velocity of LAWDS NGC 6633
7 is consistent with cluster membership. We conservatively conclude that LAWDS
7 is a viable massive double degenerate candidate, though unlikely to be a Type
Ia progenitor. Astrometric data from GAIA will likely be needed to determine if
either white dwarf is truly a cluster member.
