I'd be somewhat leery of doing it unless I knew a lot about the code base. To wit:

print " ",(join " \n",@list),"\n"; #one of many ways to indent a list

print "$var\n" ; #replaced hardcoded 'print "hello\n";' line.
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are just two of many strange things people might do that could match a s/^print(stuff)\\n(more stuff)/say $1$2/; line oddly.