The Oaklawn Park horse track at Hot Springs sold a lot of corned beef sandwiches and hot dogs on the first day of its season yesterday. It`s hard to tell if it`s because they were selling at 1904 prices -- 50 cents for the corned beef, a dime for the hot dogs -- or because there were more people at the opening than for several years past. Maybe it was both, and all the people showed up to eat the cheap food while they enjoyed a day of racing. Twenty-five-thousand, 137 people showed up for the first day of racing -- more than two-thirds again as many as attended on opening day last year. The cheap eats were to help mark 100 years since construction began on the track in 1904.