That is a lot. I would RMA the drive. Even 1 pending or bad sector means the disk is developing issues and will continue to get worse over time.
I called the retailer (B&H), explained the circumstances and they consented to RMA the drive. Prepaid label via UPS, and upon receipt they'll send me a replacement. They said that the particular drive I got is "discontinued" and they will send me the drive that replaces it in the WD line. Hope it is that indeed, suppose it's a WD Red 3TB 5400RPM. He wondered if I wanted to replace both the HDs I got in the order, I said that I had no good reason to think the other one is bad too (it's in its unopened box), and that I will attempt to format and test it, just as I did the other one (fingers crossed!).
The one they will be sending me is to replace WD30EFRX. They have the replacement listed as:
MFR # WDBMMA0030HNC-NRSN
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Edit: I have my doubts here. Looking up the replacement drive most sellers and sites don't specify that this is "Red." B&H's page says "Red," a post at WD Community asserts that it's the same HD as WD30EFRX but is the retail box version. Other than those two, Amazon, Best Buy, CNET do not indicate that this drive is "Red" much less a "replacement" for the WD30EFRX. One reason I'm concerned is that I have a couple of WD30EFRX in my NAS, and I want to save one of these to replace those in case one goes bad. I don't want incompatible drives in the RAID1 NAS. Also, I'm concerned about the quality if the drive. I have had several 2+TB HDs fail on me, going forward I want dependable HDs.
Newegg's page for the MFR # WDBMMA0030HNC-NRSN indicates not that it's "Red" but this:
WD Desktop Networking WDBMMA0030HNC-NRSN 3TB 5400 RPM 64MB Cache SATA 6.0Gb/s 3.5" Network NAS Hard Drive Retail Kit