Does inputting incorrect disk block size in a ddrescue command give errors in recovery?

I'm creating an image of my 1tb file and used the command: Sudo dd bs=976624564 if=/dev/sda of='/media/ubuntu/externaldrive/image file.img'

I checked block size with command "sudo cat /proc/partitions" and got the block size above, but when I tried "sudo blockdev--getbsz /dev/sda" I got 4096...

The first command is still running and creating the image of my 1tb disk drive in my external drive, but wanted to know if entering what I feel incorrect will gives errors in recovering data?