That’s correct if by “offer price” you mean $17.00, but the price to the underwriters is 15.98. That’s what they can buy the additional shares at, and RVNC traded well above that (but under 17) for most of December.
RVNC—Adding to what ‘mouton’ said, the underwriter’s exercise price for the greenshoe option is always identical to the underwriter’s purchase price in the main offering. A 6% discount to the nominal deal price is an industry standard (thus $15.98 in this instance).