But it still doesn't make him the pioneer.
And Jayasurya-Kalu aren't pioneers either. They are remembered because they did it in a world cup successfully that they went onto win.
It's generous to say that Kaluwitharana was a success in the World Cup. His scores were:
0 (1b) v Zimbabwe (Jayasuriya 6 off 11, partnership 5; Gurusinha 87*, de Silva 91)
26 (16b) v India (Jayasuriya 79 off 76, partnership 53; Tillekeratne 70*, Ranatunga 46*)
33 (18b) v Kenya (Jayasuriya 44 off 27; partnership 83; de Silva 145, Gurusinha 84, Ranatunga 75*)
8 (3b) v England (Jayasuriya 82 off 44; partnership 12; Gurusinha 45)
0 (1b) v India (Jayasuriya 1 off 3; partnership 1; de Silva 66, Mahanama 58*)
6 (13b) v Australia (Jayasuriya 9 off 7; partnership 12; de Silva 107*, Gurusinha 65, Ranatunga 47*)
So against Test-playing teams, he succeeded (to any extent) 1 time out of 5. Even Jayasuriya only did twice, but at least he scored 70+ in his successes.
Kaluwitharana actually did much better in the B+H series in Australia just before the World Cup, where after a bad start he had scores of 77, 50, 20, 74 and 13 (at an overall strike rate of a run a ball).