No doubt. It was not until the Gupt period that Sanskrit fully came into the forefront.
Prior to that it was sporadic, and ironically used mainly by the so called "foreign" rulers - Shak Kshatrap, Kushan, Pahlav, etc. Even the Ghosundi inscription of Parasariputr Gajyan gives the name of the chief as Sarvtat (perhaps a Pahlav cf.
https://en.wikipedia.org/wiki/Haurvatat).
As I have mentioned before, these were absolutely not foreigners to "India," but foreigners only to pauranic and modern historians from the point of view of the Prakrit/Pali belt. These were the Shak, Tukhars, and Gurjjars - all living in the Indus area.
The Gupt I see as a marriage of sorts [literally too perhaps] between the Pali/Prakrit tradition and the Sanskrit one, with the Gupts adopting Sanskrit with a vengeance. So much so that just in a few short years Sanskrit had spread in Inner Asia, South Asia - Pushppur to Banga to Damil, to even SE Asia - Vietnam and Java. Indic eras, numerology, scripts, thought, works, all spread throughout the region.
Gupt script.
"Gupta script, any of a group of Indian alphabetic writing systems (sometimes modified to represent syllables instead of single sounds) derived from a northern Indian alphabet of the 4th–6th century AD. The ruling Gupta state at that time gave the script its name. It was developed out of Brāhmī and was spread with the Gupta empire over large areas of conquered territory, with the result that the Gupta alphabet was the ancestor (for the most part via Devanāgarī) of most later Indian scripts. The original Gupta alphabet had 37 letters, including 5 vowels, and was written from left to right. Four main subtypes of Gupta script developed from the original alphabet: eastern, western, southern, and Central Asian. The Central Asian Gupta can be further divided into Central Asian Slanting Gupta and its Agnean and Kuchean variants and Central Asian Cursive Gupta, or Khotanese. A western branch of eastern Gupta gave rise to the Siddhamatrka script (c. AD 500), which, in turn, evolved into the Devanāgarī alphabet (c. AD 700), the most widespread of the modern Indian scripts."
http://www.britannica.com/topic/Gupta-script
Gupt numerals.
"If we examine the route which led from the Brahmi numerals to our present symbols (and ignore the many other systems which evolved from the Brahmi numerals) then we next come to the Gupta symbols. The Gupta period is that during which the Gupta dynasty ruled over the Magadha state in northeastern India, and this was from the early 4th century AD to the late 6th century AD. The Gupta numerals developed from the Brahmi numerals and were spread over large areas by the Gupta empire as they conquered territory."
http://www-history.mcs.st-and.ac.uk/..._numerals.html
The Legends of the Panjab
"Kahte Shahr Ujjain Rao nit karte bhog bilasa. Gaur Bangala, des jinhon ka tyag dia biswasa."
https://books.google.com/books?id=ulcIAAAAQAAJ&pg=PA2
Samudrgupt's inscription matches this massive spread.
"first capturing, and thereafter showing the favour of releasing, all the kings of
Dakshiṇāpatha ... [list]"
"the forcible extermination of many kings of
Āryāvarta ... [list]"
"obeisance by such frontier rulers ... [list]"
"by the
Dēvaputra-Shāhi-Shāhānushāhi and the Śaka lords"
"all
Island countries, such as Siṁhala and others."
ARCHAEOLOGICAL SURVEY OF INDIA, CORPUS INSCRIPTIONUM INDICARUM, VOLUME III
INSCRIPTIONS OF THE EARLY GUPTA KINGS