Pre-order numbers for Apple’s (NASDAQ:AAPL) new iPhone 5c have not yet been announced by the company and rumors have suggested that the iPhone 5s’ launch inventory could be severely limited due to supply constraints, but this has not stopped an analyst from estimating that the combined launch weekend sales of both the iPhone 5s and iPhone 5c could touch the 8-million mark.

According to Ming-Chi Kuo of KGI Securities, Apple will likely ship six million to eight million iPhone 5s and iPhone 5c units during the first weekend following the devices’ launch on Friday. And, if the estimate turns out to be accurate, it will exceed the iPhone 5’s initial sales figure of five million units last year.

Kuo told in a research note obtained by Apple Insider that not revealing the iPhone 5c's pre-order numbers could be Apple’s strategy to keep the breakdown of actual iPhone 5s and iPhone 5c sales from rival manufacturers. The analyst also said that Apple is not likely to disclose anything on the sales front until after the launch weekend -- a ploy the company used in 2012 after the launch of the iPad 4 and iPad mini.

Breaking down the sales, Kuo estimated that the iPhone 5s could account for only 35 percent to 45 percent of total sales, while the iPhone 5c could make up for the remainder. 

According to Kuo, Apple did not make the iPhone 5c a low-cost product as it could have cannibalized sales of the higher-priced iPhone 5s. However, the analyst believes that Apple could eventually cut the iPhone 5c’s price once the initial demand for the 5s handset is satisfied.

Kuo’s estimates appeared to be a bit generous compared to forecasts by Gene Munster of Piper Jaffray, who projected that Apple could sell five million to six million iPhone units during the launch weekend.

“Given last year's in-store sales numbers, we are comfortable that Apple could sell 2.5 million iPhone 5S units this launch weekend,” Munster said in a report to investors, obtained by Apple Insider. “Our estimate for the 5C is 3 million units sold during the launch weekend including 1 million online pre-orders and 2 million in stores.”

According to Munster, the Chinese market, which will be part of a global iPhone launch for the first time, will account for about 10 percent to 15 percent of total iPhone unit sales.

Apple-authorized retail stores will begin selling the iPhone 5s on Friday at 8 a.m. local time in the respective time zones, while the phone will hit the company’s online store for purchase on Sept. 20 at 12:01 a.m. PDT (3.01 a.m. EDT).