modded address

Greetings,

TMDA 1.0.3 / netqmail 1.0.5 under SGI IRIX 6.5.20m

In an incoming filter file, should not the line:
from sparky*@domain.com drop
allow incoming mail from "[email protected]" but drop incoming mail from 
"[email protected]"

Likewise, shouldn't the line:
from [email protected] drop
drop any and all incoming mail from "[email protected]"

I've a couple of TMDA protected addresses that have recently picked up a 
bit of spam.  I'm finding that the From address is a modified form of a 
legitimate address, (usually just a couple of characters added to the 
end of the first part of the address as in the example above).

It's been a couple of years since I set this system up, so I'm not 
currently as familiar with it as when initially set up.

Thanks,
Dave