I assume that this is a problem from the rcp command itself,
because if you try the same in a terminal you also get 0 as return value.

rcp mine.txt cmd1.txt; echo $?
/bin/cp: mine.txt:cannot access min.txt
0
[download]

but if you use cp you'll get a correct return value:

cp mine.txt cmd1.txt; echo $?
/bin/cp: mine.txt:cannot access min.txt
1
[download]

maybe it's possible for you to use cp instead of rcp.

MP