No, that doesn't work. The unbackslashed @ eats up all the prototype characters behind it.

This:

#!/ActivePerl/bin/perl

use 5.014;
use warnings;

sub sayit (@;_);

sayit (1, 2, 3);

my @list = (4, 5, 6);
sayit (@list);

local $_ = 7;

sayit;

my $_ = 8;

sayit;

sub sayit (@;_) {

   my @list = @_;

   if (@list) { say "@list" } else { say "no list" }

}
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yields this:

Prototype after '@' for main::sayit : @;_ at q.pl line 6.
Prototype after '@' for main::sayit : @;_ at q.pl line 21.
1 2 3
4 5 6
no list
no list
[download]

The first two lines are due to the warnings pragma.