We apparently forgave J.C. Penney (NYSE:JCP) two weeks ago, and now the struggling retailer is grateful.

"We brought back the things you like about J.C. Penney, gave you new things to explore, and now we're happy to say you've come back to us," offers up the struggling department store chain's latest warm-fuzzy commercial. "We're speechless, except for two little words: Thank you."

How about two more little words: fact check.

J.C. Penney stock may be up 35% since bottoming out last month, but there are no signs of customers coming back. The chain reports its latest quarterly financials on Thursday, and it won't be pretty. Despite the new ad's implications that customers have come back, the actual numbers will likely tell a different story.

It's not just a bearish hunch. J.C. Penney announced some preliminary financials last week.

Same-store sales fell a whopping 16.6% during the fiscal first quarter that ended on May 4. And -- just so we're clear here -- this comes after an 18.9% slide during the prior year's fiscal first quarter. This means that comps have plunged 32.4% over the past two years.

Are customers really back?

Naturally, bulls will argue that the retailer's brandishing some swagger based on more recent trends, but be careful of any false optimism that J.C. Penney may offer on Thursday afternoon. Keep in mind that comps during the fiscal second quarter of last year tumbled 21.7%. Arguing that the pace of defections is decelerating or that comps have been flat during the first few days of the new fiscal quarter isn't a sign of folks coming back. Same-store sales would have to climb 27.7% -- yes, 27.7% -- to get back to where the chain was two years earlier.

J.C. Penney doesn't just need the negative comps to stop. That would only prove that its thinning shopper base has stabilized. The retailer has a long way to go to prove that customers truly have come back.

Retailers don't always bounce back. Shoppers are fickle. Great chains falter. There are the occasional turnaround stories: Pier 1 Imports stock traded for as little as $0.10 four years ago when the home furnishings specialist seemed to be on the brink of bankruptcy. It bounced back to become a profitable and growing company.

If J.C. Penney can turn things around, it won't happen right away. The commercial's lying. The retailer may want to convince consumers that they're back, but investors with hard numbers know the truth.

There are no signs that undoing a year of Ron Johnson's poorly received changes will do anything more than take J.C. Penney back to where it was a year earlier, when the brand was languishing so badly that it brought in a radical retailer guru in Johnson.

I liked J.C. Penney better when it was apologizing two weeks ago. Gloating is unbecoming, especially when there's nothing to gloat about.

Longtime Fool contributor Rick Munarriz has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.