Some dealers will release the firearm according to the law and others will not
https://app.leg.wa.gov/rcw/default.aspx?cite=9.41.090
RCW 9.41.090(6)(c)
The dealer shall, by the end of the business day, sign and attach his or her address and deliver a copy of the application and such other documentation as required under subsections (1) and (2) of this section to the chief of police of the municipality or the sheriff of the county of which the purchaser is a resident, or the state pursuant to subsection (3)(b) of this section. The triplicate shall be retained by the dealer for six years. The dealer shall deliver the pistol or semiautomatic assault rifle to the purchaser following the period of time specified in this chapter unless the dealer is notified of an investigative hold under subsection (5) of this section in writing by the chief of police of the municipality, the sheriff of the county, or the state, whichever is applicable, or of the denial of the purchaser's application to purchase and the grounds thereof. The application shall not be denied unless the purchaser is not eligible to purchase or possess the firearm under state or federal law.