I agree with Brian, that it is difficult to assign either Indian or Arabian origins to this distinct form of sword as it is in effect both. As Jens has noted, the key to most diffusion of culture, in which we focus primarily on weapons, has been carried via trade.
As has also been noted, these swords are described in Elgood ("The Arms and Armour of Arabia") as 'Hadhrami', essentially from Hadhramaut in southern Arabia, as part of the Yemen. In this reference, Elgood illustrates three sabres of this distinct hilt form (2.9, 2.10 and 2.11, p.13-14) and in the text discusses the Hadhrami as frequently serving as mercenaries in Hyderabad. Here he notes that "..the swords are certainly made there and locally" (p.15), with one of the swords illustrated noting that the scabbard is likely locally made.
There are a number of other key elements which connect the various Arabian swords from this region to probable Indian manufacture, as described further in Elgood.
These Arabian swords have the distinct nimcha type nock at the base of the grip, but the curious hilt form begs more explanation. The obliquely canted
pommel seems to recall another familiar hilt form, and if I may dare to use 'free association'
reminds me of similar hilts from the Indonesian archipelago, particularly Sumatra. I looked through Van Zonneveld ("Traditional Weapons of the Indonesian Archipelago") and found various forms of klewang, pakayun, andar andar etc. which seemed to favor the same oblique pommel shapes. One example emphasized the triple feature at the pommel ,'hulu boh glima' (p.52) which suggested the pomegranate as the source of the stylized hilt form.
With the heavy Arab trade that extended from Malabar and into Ceylon with extensions into Malaysian and Indonesian regions as well, it seems quite plausible that such exotica might have returned to Arabia via India, especially as the prevalence of Indian made swords has been established. As always, stylized motif and form tends to degenerate as it becomes more removed from its origin, whether by time, distance, or both.
For another interesting comparison, in the Elgood illustrations of the Hadhrami sabres in 2.9 and 2.10, look at the chowk on the crossguards and note the crosslike geometric floral device at the center, then look at the Tatar sabre on the thread with that title posted by Perkun...the crosslike floral device is strikingly similar on the 17th century Tatar sabre. Another very interesting possibility in cultural diffusion!.
Best regards,
Jim