Grazon P+D??

Planted 25 acres of orchard grass last August and now have a awesome stand, but of course I gotta spray it. Dead nettle is my main weed, but had some pig weed in it last year. After researching grazon p+d it seems to be a lot more effective on dead nettle and the other few weeds I have in the stand. Also read it has a long residual so I'm hoping what pig weed I may still have will be controlled. What's everybodys thoughts on it? Will it harm first year grass at all? Right now it's 8-12" tall and growing beautifully.

Grazon P+D??