Winnebago Industries (NYSE:WGO), the best-known brand in motor homes, is set to report earnings results for its fiscal fourth quarter on Thursday, Oct. 16. Despite its solid profit and sales growth, investors in this small-cap stock have endured a bumpy ride lately: Shares are down 15% in the past three months, compared to a 5% dip in the S&P 500.

Is that underperformance just another example of Wall Street's shortsighted attitude? Let's take a closer look by highlighting a few metrics for investors to keep an eye on in this week's earnings report. 

1. Continued growth in deliveries

Winnebago is riding a strong recovery in demand for its products. Just in fiscal 2013, for example, total motor-home deliveries spiked higher by almost 50% year over year. And annual sales are now at roughly four times the recessionary low from 2009.

Source: Winnebago.

Winnebago's sales growth has slowed a bit in the current fiscal year. Deliveries are trending at 30% higher through the past nine months. While that still points to strong demand for its product lineup, RV shoppers are sensitive to changes in the broader economy. As a result, investors will be looking for evidence of a continued sales recovery for these luxury products. That would show up in the form of higher unit sales to both dealers and retail customers.

Overall, Wall Street expects Winnebago to post 14% sales growth for the quarter, to reach $245 million. That would mirror last quarter's 14% revenue improvement and lead to a total of roughly $834 million in sales for fiscal 2014, about 4% better than last year's haul.

2. Improving gross margin trends

Winnebago's profitability is already within striking distance of its pre-recession high. Last quarter, gross margin climbed by a full percentage point to reach 10.7%. 

WGO Gross Profit Margin (Quarterly) data by YCharts.

A number of factors drove that profit improvement, but the two biggest were overall sales growth and pricing strength in the company's growing towables business.

Investors can expect both trends to continue into Winnebago's fourth quarter, which should lead to earnings growth that is again well ahead of revenue improvements. In fact, Wall Street analysts are aiming for Winnebago's earnings per share to jump by 23% to $0.46 this quarter.

3. A steadier backlog

In the last quarter, Winnebago's motor-home order backlog fell by 25% from the prior year to $220 million. That dip understandably spooked some investors. After all, the figure represents unfulfilled orders that the company expects to ship in the next six months. A large drop in backlog could be an early sign that demand is softening. However, management told investors that wasn't the case here. CEO Randy Potts explained in a conference call with analysts that the backlog drop reflected increased production rates and a more rational inventory level at dealerships:

We couldn't sustain those kinds of backlog levels. It wasn't good for our business or our dealers' business. It just put the production too far out. Really the current backlog level is I think more typical for us of where it would be in a normal growth and sustained growth pattern.

Consistent with that explanation, investors should expect no major changes in Winnebago's backlog this quarter. A steady figure around $200 million would mean management has a good handle on forecasting RV demand, and that solid sales growth should continue into Winnebago's new fiscal year.