The publication title filed with the U. S. Copyright Office is "Plastic man in the Game of death!" No issue number is included in the filing.
The indicia text:
"This book has been manufactured under wartime conditions in full compliance with all orders and regulations of the War Production Board, in particular 1. 245
By
VITAL PUBLICATIONS, Inc.
New York
from
material prepared and supplied
by
COMIC MAGAZINES
Copyright 1943, Vital Publications, Inc., New York All Rights Reserved
The indicia scan confirms that there is no volume, issue number, or frequency present.
Judging from the cover, copyright registration, and the indicia text, it appears this book was originally intended as a stand-alone publication and not part of a series. The Copyright Office treated it as such; the filing is listed in the Pamphlets volume and not the Periodicals one, which is how the Office treats stand-alone. There doesn't appear to have been a copyright filing for the second issue (from 1944), but the cover and indicia point to that being published as a stand-alone as well. This doesn't seem to have become a proper periodical series until the third issue in 1946.
Police Comics (Quality Comics, 1941 Series) #27 (February 1944) is copyright 1943, and per the Copyright Office, its publication [on-sale] date was December 15, 1943, before this comics' Copyright Office's publication [on-sale] date of December 29, 1943. Police Comics (Quality Comics, 1941 Series) #28 (March 1944) is copyright 1944, and its Copyright Office's publication [on-sale] date is January 14, 1944. Thus, it is probable that this issue appeared on the newsstands at the same time Quality Comics titles with a February cover date in between Police Comics #27 and #28.