Is it normal to not have lower pole fullness?

Allow about 4 months for your breasts to even out and assume a more natural breast shape. It's called dropping and fluffing, and it sounds like you haven't had that happen yet which is normal for some patients at just over a month after recovery. I think you may want to ask your surgeon for some advice about helping the dropping and fluffing.

An explanation of my impression of what we mean when we talk about implants dropping. 

Submuscular implants are sitting as if they are at the bottom of an envelope. The breast fold, like the bottom of the envelope keep the implants from descending. At the upper pole is a large space under the muscle, and that space goes up to the clavicle (collar bone). Typically the implant position looks fine at surgery. As the patient awakens, the relaxed pectoralis muscle contracts, pushing on the implant. This displaced the silicone (or saline) which bulges into the upper pole, the only direction with room to expand. The lower pole of the breast may seem to empty out. But the implant itself doesn't actually move. As the muscle relaxes over several month, the upper pole no longer bulges and the implant position looks like it did in surgery.

This process can take up to 6 months. If your surgeon was happy with the implant position at the end of the surgery, it is highly likely that your implants will settle into position, filling out the lower pole, and ending the fullness in the upper pole.

Thanks for your question, best wishes.