Assuming you were using the whole disk as the lvm pv, rather than an individual partition within it, it should generally be just fine since the LVM header is not in the first sector, where the partition table is, especially when using 512-byte sectors.
The partition table is in the first sector:
See for example here: Hard disks can be divided into one or more logical disks called partitions. This division is recorded in the partition table, found in sector 0 of the disk.
The LVM header is by default in the second sector:
See for example here: By default, the LVM label is placed in the second 512-byte sector. You can overwrite this default by placing the label on any of the first 4 sectors. This allows LVM volumes to co-exist with other users of these sectors, if necessary.
Beware: I am unsure what happens if the sector size fdisk uses is larger, say 1024-bytes - LVM might still be in the second 512-bytes sector, and fdisk might overwrite the whole 1024-byte sector?
As an aside: If you are unsure and have access to additional space (e.g. on Amazon EC2), you could always create a volume of identical size, do a pvcreate on it, add it to the volumegroup, use a pvmove to move the data to the new volume, and then a vgreduce to remove the affected volume.