1962 Topps Number 1 Maris autographed card
 

Does only PSA dual grade ?
Signature is authentic (by SGC) but would like to have it dual graded
Wondering what grade the card would receive

That's a good question. Just based on the corners, I would expect a PSA 6 or 6.5. However, since the card is signed with a ball point pen, you can see the deep impressions that the signature makes into the surface of the card in "Roger". If PSA downgrades for those as well, maybe a 2.5 or 3?
I think you'd just have to send it in and find out. Could you declare $499 and have it dual graded by PSA for $20 plus shipping? Their next level for that service is $75 for cards declared up to $1999.

It’s a nice card. I don’t know that a dual grade is going to help you. I would think that the card grade is probably no better than a 5 based on those corners. The ball point pen auto is not gong to grade high. It’s a great card with strong eye appeal. You may do better to have it crossed over anyway but dual grading may reveal it’s worse than it appears to be.

Nice card. Main thing for that issue is that it's centered (I have two right now that are not...) Depends on what you want to do with it, but if you are keeping it I don't see the point in anything more than the authentication it currently has. I would agree PSA 5 or 6 just based on the scan.

Much rather have this card signed in ball point pen than a Sharpie.

Ha, good point.