WAL oddities (8.0.3)

First, are WAL files not allowed to end in FF?

I was looking at the logs and it jumps straight from
0000000100000194000000FE to 000000010000019500000000.

Yet other times it seems to end in an F: 0000000100000194000000EF.

Second, we have log archival enabled and the system it was archiving to
was unavailable. Once that system was brought back, everything resumed
appropriately and the files were copied over.

However, now I'm left with a pg_xlog directory that is about 7 GB in
size. All of the files but the most recent has a corresponding
archive_status/$FILE.done file. Will PostgreSQL eventually remove most
of these unnecessary files or am I stuck with them?

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