No.

perl -Dt -e '"$a$b".$c.$d'   

EXECUTING...

(-e:0)    enter
(-e:0)    nextstate
(-e:1)    gvsv(main::a)
(-e:1)    gvsv(main::b)
(-e:1)    concat
(-e:1)    gvsv(main::c)
(-e:1)    concat
(-e:1)    gvsv(main::d)
(-e:1)    concat
(-e:1)    leave
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They both call the concat opcode.

At one time, I remember the tokenizer actually rewrote "x$y" to be "x" . $y and "recursed" on it. But it doesn't seem to anymore. O::Deparse can even tell the difference:

perl -MO=Deparse -e '"$a$b".$c.$d'
"$a$b" . $c . $d;
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