White Circle 384 is mentioned a few times in the articles about Spillane. For instance:
"This Canadian White Circle series has 300+ books (actually 459) in it published from the late 40s to early 60s (no - 1942 to 1952). White Circle #384 is the most scarce (no - 10 of both printings are now for sale on line; a few titles from 1942 are truly rare), pricey (yes) and soughtafter [sic] book (yes - see price) in the series and does not often turn up in condition (yes but more often that many of the White Circles). There were also at least 2 reprintings of the book in 1949 with the same number (no - only 1 reprint), the chief difference being the colors on the cover are brighter than the darker tones of the first printing from 1948 (yes)."
Most of the errors are thanks to a long time dealer who, in the 1980s, published a White Circle checklist full of errors. It is still available on his web site.
Paperback Parade 46 - August 1996
White Circle 384 - 1948 (first printing)
White Circle 384 - 1949 (second printing)