Bear in mind that prior to desktop publishing tools (which arrived circa 1986-88) laying out a magazine/large format book like WER was a time-consuming and labour intensive job; typesetting was a photographic process using a phototypesetter to etch the printing plates
at best (digital phototypesetting was around but very bleeding-edge), and printing was also a mechanical process. Even with a streamlined workflow, allocating an entire month to the production process would make it a tight fit. Then add another month for distribution around the US (most likely via railfreight to intermediate wholesale warehouses before bundles were shipped out to bookstores). Finally note that the date on the cover of a periodical is
when the store clerks take the item off sale and strip the covers to return them as evidence of destruction in return for credit (any sold -- no covers provided -- copies must then be paid for, to the wholesaler and ultimately the publisher).
If that sounds like a stone-age process ... well, it's the way publishing used to be done: it predates computerization and containerization by some decades, and it was only beginning to change in the 1980s.
To make matters worse, the writing/editing process would be mediated entirely by sending drafts back and forth via the mail, so you can reasonably add a couple of weeks to the process of writing and then approving a draft compared to what it would take today.
Upshot: this issue was probably finalized 3-4 months before the date on the cover. Microsoft Word was quite possibly not available to reviewers in time to make it into the magazine.
(Source: I used to write software reviews for Computer Shopper -- the British version of the title, not the same as the US one -- in the late 80s to early 90s. Smaller country, different tech by then, but it was still a tedious back-and-forth with printed drafts in envelopes with stamps on them (and sometimes floppy disks!).)